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Sample records for intrusion east greenland

  1. Field relations and geochemistry of the Ruinnæsset intrusion and related magmatic rocks of the Archaean Skjoldungen province, East Greenland

    DEFF Research Database (Denmark)

    Blichert-Toft, Janne; Rosing, Minik T.; Lesher, C.E.

    1992-01-01

    Archaean alkaline rocks, Skjoldungen, East Greenland, Ruinnæsset intrusion, hornblende, major and re elements......Archaean alkaline rocks, Skjoldungen, East Greenland, Ruinnæsset intrusion, hornblende, major and re elements...

  2. Lithologic mapping of mafic intrusions in East Greenland using Landsat Thematic Mapper data

    Science.gov (United States)

    Naslund, H. Richard; Birnie, R. W.; Parr, J. T.

    1989-01-01

    The East Greenland Tertiary Igneous Province contains a variety of intrusive and extrusive rock types. The Skaergaard complex is the most well known of the intrusive centers. Landsat thematic mapping (TM) was used in conjunction with field spectrometer data to map these mafic intrusions. These intrusions are of interest as possible precious metal ore deposits. They are spectrally distinct from the surrounding Precambrian gneisses. However, subpixel contamination by snow, oxide surface coatings, lichen cover and severe topography limit the discrimination of lithologic units within the gabbro. Imagery of the Skaergaard and surrounding vicinity, and image processing and enhancement techniques are presented. Student theses and other publications resulting from this work are also listed.

  3. Lateral Reactive Infiltration in a Vertical Gabbroic Crystal Mush, Skaergaard Intrusion, East Greenland

    Science.gov (United States)

    Namur, O.; Humphreys, M.; Holness, M. B.

    2012-12-01

    The Marginal Border Series of the Skaergaard intrusion (East Greenland) is comprised of rocks having crystallized in situ along the vertical walls of the magma chambers. It is subdivided into an outer Unbanded Division and an inner Banded Division. The Banded Division contains abundant cm- to dm-thick bands dominated by fine-grained mafic minerals, with a morphology evolving from almost planar to deeply scalloped and fingered with increasing distance from the intrusion margin. The morphology of these bands is reminiscent of the reaction fronts described in sedimentary basins infiltrated by reactive fluid. We propose that the banding in the Skaergaard Marginal Border Series is produced by chemical disequilibrium into the crystal mush resulting from the suction of primitive liquid from the main magma body into the crystal mush. Shrinkage of the mush during solidification is the driving force for liquid migration. Liquid porous flow produces partial dissolution of evolved pre-existing mafic minerals in the mush, which changes the new mush liquid composition to one capable of crystallizing mafic rocks with a very minor plagioclase component. Abrupt solidification of this liquid, which results in the formation of the actual colloform bands, is explained by supersaturation of some mafic mineral components (e.g. olivine, clinopyroxene, Fe-Ti oxides) in the infiltrating melt. The morphological evolution of the colloform bands, from almost planar to deeply scalloped and fingered with increasing distance from the intrusion margin, is thought to result from increasing crystal mush thickness with progressive differentiation.

  4. Valanginian ammonites in East Greenland

    DEFF Research Database (Denmark)

    Alsen, Peter

    2001-01-01

    ammonites, Boreal, Tethys, bed-by-bed collection, Valanginian, Wollaston Forland, East Greenland......ammonites, Boreal, Tethys, bed-by-bed collection, Valanginian, Wollaston Forland, East Greenland...

  5. The campsite dykes: A window into the early post-solidification history of the Skaergaard Intrusion, East Greenland

    Science.gov (United States)

    Holness, Marian B.; Richardson, Chris; Andersen, Jens C. Ø.

    2013-12-01

    The Skaergaard Intrusion of East Greenland is cut by several generations of dykes, the earliest of which is thought to have intruded shortly after solidification of the Skaergaard. Two ~ 6 m wide doleritic dykes from the earliest generation are exposed in the campsite area near Homestead Bay of the Skaergaard Peninsula. One of the dykes (the Campsite Dyke) locally contains abundant xenoliths of troctolitic cumulate. The other (the Plagioclase-phyric Dyke) contains abundant large plagioclase phenocrysts. Cross-cutting relationships between the two dykes are not exposed. The median clinopyroxene-plagioclase-plagioclase dihedral angle, Θcpp, in the Campsite Dyke is 88-89.5°, whereas that of the Plagioclase-phyric Dyke is 79°. Using an empirical relationship between Θcpp and the duration of crystallisation derived from dolerite sills, the observed Θcpp suggests that the Campsite Dyke is the older of the two, intruding the Skaergaard when it had cooled to 920-970 °C. The Plagioclase-phyric Dyke intruded later, once the Skaergaard had cooled below 670 °C. The troctolitic xenoliths divide into two separate groups. Type A xenoliths have microstructures similar to those of the Skaergaard Layered Series although mineral compositions are generally more primitive than those of the exposed cumulates - this type of xenolith is likely to have been derived from either deeper levels in the Skaergaard Intrusion or from a closely-related underlying magma chamber. One Type A xenolith has mineral compositions and Θcpp consistent with an origin in LZb of the Layered Series - this xenolith contains partially inverted pigeonite, suggesting that inversion of low-Ca pyroxene in the lower part of the Layered Series took place after the intrusion had completely solidified. Type B xenoliths are characterized by plagioclase containing large and abundant melt inclusions. Comparison with the microstructures of glassy crystalline nodules from Iceland points to a multi-stage cooling history

  6. Platinum-group mineralization at the margin of the Skaergaard intrusion, East Greenland

    Science.gov (United States)

    Andersen, Jens C. Ø.; Rollinson, Gavyn K.; McDonald, Iain; Tegner, Christian; Lesher, Charles E.

    2017-01-01

    Two occurrences of platinum-group elements (PGEs) along the northern margin of the Skaergaard intrusion include a sulfide-bearing gabbro with slightly less than 1 ppm PGE + Au and a clinopyroxene-actinolite-plagioclase-biotite-ilmenite schist with 16 vol% sulfide and 1.8 ppm PGE + Au. Both have assemblages of pyrrhotite, pentlandite, and chalcopyrite typical for orthomagmatic sulfides. Matching platinum-group mineral assemblages with sperrylite (PtAs2), kotulskite (Pd(Bi,Te)1-2), froodite (PdBi2), michenerite (PdBiTe), and electrum (Au,Ag) suggest a common origin. Petrological and geochemical similarities suggest that the occurrences are related to the Skaergaard intrusion. The Marginal Border Series locally displays Ni depletion consistent with sulfide fractionation, and the PGE fractionation trends of the occurrences are systematically enriched by 10-50 times over the chilled margin. The PGE can be explained by sulfide-silicate immiscibility in the Skaergaard magma with R factors of 110-220. Nickel depletion in olivine suggests that the process occurred within the host cumulate, and the low R factors require little sulfide mobility. The sulfide assemblages are different to the chalcopyrite-bornite-digenite assemblage found in the Skaergaard Layered Series and Platinova Reef. These differences can be explained by the early formation of sulfide melt, while magmatic differentiation or sulfur loss caused the unusual sulfide assemblage within the Layered Series. The PGEs indicate that the sulfides formed from the Skaergaard magma. The sulfides and PGEs could not have formed from the nearby Watkins Fjord wehrlite intrusion, which is nearly barren in sulfide. We suggest that silicate-sulfide immiscibility led to PGE concentration where the Skaergaard magma became contaminated with material from the Archean basement.

  7. Enigmatic Late-Stage Textures In Mafic Cumulates: Skaergaard Intrusion, East Greenland.

    Science.gov (United States)

    Stripp, G.; Holness, M.; Veksler, I.

    2006-12-01

    The complexities of slow solidification in deep-seated silicate liquid bodies are poorly understood. Late-stage melt migration, due to compaction of the crystal mush, drives re-crystallisation and metasomatism which can have significant effects on chamber-wide chemical evolution. In this contribution we present novel textural observations from mafic cumulates of the Skaergaard Layered Intrusion which may shed light on liquid movement during the last stages of solidification of the crystal mush. Previously undescribed mafic symplectites are widespread in the Skaergaard Layered Series, and comprise vermicular intergrowths of plagioclase and olivine, which may be replaced by clinopyroxene in the outer parts of the symplectite. The symplectites grow outwards from Fe-Ti oxide grains, consuming adjacent cumulus plagioclase. In the Middle Zone of the Layered Series (where symplectites are best developed) symplectite plagioclase adjacent to the Fe-Ti oxide grains contains 1.2 wt% FeOtot which decreases to 0.6 wt% FeOtot at the symplectite margin, compared to a ~ 0.35 wt% average for adjacent cumulus plagioclase. Symplectite plagioclase is up to 40 mol% more An-rich than the adjacent cumulus grains. Olivine compositions range from Fo45 to Fo32 along the growth direction of the symplectite, compared to ~ Fo44 for cumulus olivine at this level in the intrusion. Biotite commonly replaces olivine. Texturally- and compositionally-related patches of intergrown clinopyroxene and An-rich plagioclase occur locally on plagioclase triple junctions and plagioclase grain boundaries. Symplectites are present, but rare, in the lower parts of the Skaergaard Layered Series; increase significantly in volumetric importance in Lower Zone b; are very common in Middle Zone and disappear in UZ. The symplectites resemble those formed by hydrous partial melting of oceanic gabbros (Koepke et al., 2005) but important differences include the presence of clinopyroxene and Fe-rich plagioclase, and the

  8. A Textural Record of Silicate Liquid Immiscibility in the Skaergaard Intrusion, East Greenland.

    Science.gov (United States)

    Stripp, G.; Holness, M.; Veksler, I.; Nielsen, T.; Tegner, C.

    2008-12-01

    The extent of silicate-liquid immiscibility in differentiated basaltic systems is widely debated despite its great potential importance in controlling the liquid line of descent. While the onset of liquid immiscibility in the bulk magma is likely to occur late in the fractionation history in basaltic systems, the interstitial liquid trapped in the developing crystal mush may reach the miscibility gap earlier in the solidification history. We present previously unreported symplectite textures from the Skaergaard Intrusion. The replacement of cumulus crystal rims by reactive symplectites of olivine or orthopyroxene and plagioclase, together with growth of vermicular ortho- and clinopyroxenes, An-rich plagioclase, Fe-Ti oxides and apatite is common in lower and mid-levels of the Layered Series and very common in the Triple Group and mineralized horizons. In contrast, the Upper Zone of the Layered Series and the Marginal Border Series contain co-existing, non-reacting granophyric and ilmenite-rich symplectites filling interstitial pockets between cumulus grains. We suggest that reactive mafic symplectites grew during chemical disequilibrium caused by the separation of conjugate immiscible interstitial liquids and selective loss of the Si-rich component from the crystal mush. We anticipate that Upper Border Series contains reactive granophyric segregations due to the preferential loss of the dense Fe-rich conjugate liquid. Non-reactive ilmenite-rich intergrowths and associated granophyres formed by in-situ crystallisation of late-stage immiscible interstitial liquids. Reactive mafic symplectite formation and, by inference, the best developed interstitial liquid phase separation, coincides with the mineralized horizons of the Triple Group suggesting a genetic link between the two.

  9. Applications of Landsat Thematic Mapper and ground-based spectrometer data to a study of the Skaergaard and other mafic intrusions of East Greenland

    Science.gov (United States)

    Birnie, Richard W.; Naslund, H. Richard; Nichols, Jennifer D.; Turner, Patricia A.; Parr, J. Thomas

    1989-01-01

    Landsat TM data have been used in conjunction with field spectrometer data to map the lithologic units associated with a series of gabbroic intrusions in the East Greenland Tertiary Igneous Province. The general lack of vegetation combined with the difficulty of access to these intrusions make them ideal candidates for lithologic mapping using remote sensing techniques. In addition, these bodies are of interest as possible precious metal ore deposits. The intrusions are spectrally distinct from the surrounding Precambrian gneisses; however, subpixel contamination by snow, oxide surface coatings, and lichen cover and severe topography limit the discrimination of lithologic units within the gabbro. The spectral nature of the surface contaminants was evaluated with a Barringer Hand Held Ratioing Radiometer (HHRR). These HHRR data indicate that bare rock exposures have distinct TM signatures for each lithologic unit but that even small amounts of subpixel contamination are enough to mask these differences because of the large differences between the TM signatures of the rocks and the contaminants.

  10. Pressure conditions for the solidification of the Skaergaard intrusion: Eruption of East Greenland flood basalts in less than 300,000 years

    Science.gov (United States)

    Larsen, Rune B.; Tegner, Christian

    2006-11-01

    Primary granophyres are differentiated from olivine tholeiitic magma and occur interstitially throughout the cumulus stratigraphy of the Skaergaard intrusion, East Greenland. Samples from the Lower Zones a-c (LZa-c), the Middle Zone (MZ) and the Sandwich Horizon (SH) are included in the present study together with granophyric accumulations in gabbroic pegmatite from LZa-c. Fluid inclusions in quartz and the mineral assemblage in the granophyres record the pressure under which the Skaergaard intrusion crystallised. Pegmatitic granophyre from LZa-c consists mainly of quartz, plagioclase (An 4-7) and alkali feldspar (Or 40-80) enclosing an earlier formed assemblage of ferrohastingsitic and ferroedenitic hornblende, fayalite (Fo 4-5), titanite, biotite and fluor-apatite. Granophyric quartz, albite and alkali feldspar crystallised from water-saturated granitic melts near eutectic minimum conditions between 680 and 660 °C. The pressure of granophyre crystallisation was modelled by the intercept between fluid inclusion isochores and the minimum melt solidus for granitic compositions. Pressures, recalculated to the roof pendant of the intrusion, are 0.7 ± 0.5 for LZa, 2.0 ± 0.2 for LZb-c, 2.3 ± 0.8 for MZ (the Triple Group level) and 3.3 ± 1.3 kb for SH. Amphibole geobarometry, independently, confirm the pressure estimates for pegmatitic granophyres in LZa-c. The granophyres formed as the intrusion cooled through the minimum melt solidus in LZa, LZb, LZc, MZ and SH, respectively. The pressure increase from LZa to SH granophyres is explained by progressive burial during cooling of the intrusion and contemporaneous outpouring of 5.3-6.3 ± 2.7 km of flood basalts during the initial opening of the Northeast Atlantic Ocean. Accordingly, the Skaergaard intrusion evolved from a subvolcanic magma chamber at emplacement to a more deep-seated igneous system during terminal crystallization when the majority of the intercumulus phases formed. The present cooling history suggests

  11. Extreme enrichment of Se, Te, PGE and Au in Cu sulfide microdroplets: evidence from LA-ICP-MS analysis of sulfides in the Skaergaard Intrusion, east Greenland

    Science.gov (United States)

    Holwell, David A.; Keays, Reid R.; McDonald, Iain; Williams, Megan R.

    2015-12-01

    The Platinova Reef, in the Skaergaard Intrusion, east Greenland, is an example of a magmatic Cu-PGE-Au sulfide deposit formed in the latter stages of magmatic differentiation. As is characteristic with such deposits, it contains a low volume of sulfide, displays peak metal offsets and is Cu rich but Ni poor. However, even for such deposits, the Platinova Reef contains extremely low volumes of sulfide and the highest Pd and Au tenor sulfides of any magmatic ore deposit. Here, we present the first LA-ICP-MS analyses of sulfide microdroplets from the Platinova Reef, which show that they have the highest Se concentrations (up to 1200 ppm) and lowest S/Se ratios (190-700) of any known magmatic sulfide deposit and have significant Te enrichment. In addition, where sulfide volume increases, there is a change from high Pd-tenor microdroplets trapped in situ to larger, low tenor sulfides. The transition between these two sulfide regimes is marked by sharp peaks in Au, and then Te concentration, followed by a wider peak in Se, which gradually decreases with height. Mineralogical evidence implies that there is no significant post-magmatic hydrothermal S loss and that the metal profiles are essentially a function of magmatic processes. We propose that to generate these extreme precious and semimetal contents, the sulfides must have formed from an anomalously metal-rich package of magma, possibly formed via the dissolution of a previously PGE-enriched sulfide. Other processes such as kinetic diffusion may have also occurred alongside this to produce the ultra-high tenors. The characteristic metal offset pattern observed is largely controlled by partitioning effects, producing offset peaks in the order Pt+Pd>Au>Te>Se>Cu that are entirely consistent with published D values. This study confirms that extreme enrichment in sulfide droplets can occur in closed-system layered intrusions in situ, but this will characteristically form ore deposits that are so low in sulfide that they do

  12. Formation and Cross-Cumulus Migration of Silica-Rich Liquids in the Skaergaard Intrusion, East Greenland

    Science.gov (United States)

    Larsen, R. B.; Sorensen, B. E.; Muller, A.

    2008-12-01

    In a recent publication on the Skaergaard intrusion evidence for the formation of silica-rich melts by silicate- silicate liquid immiscibility was proposed (Jakobsen et al., Geology 33, 2005). Coexisting iron-rich and silica- rich microscopic melt inclusions were trapped in apatite during crystallisation of the Skaergaard melts. Given this evidence for liquid immiscibility it is possible to explain the formation of macroscopic accumulations of silica rich entities throughout the magmatic stratigraphy. Previously, the formation and emplacement of these granophyric entities were challenging to explain. Examples include decimetre to metre size granophyric /melano-granophyric aggregates in either gabbroic pegmatite, in chimney shaped columns intersecting the layering or in isolated pods. Particularly, the presence of numerous granophyric pods a few metres above large gabbroic pegmatite were enigmatic. Moving the granophyric melts from the pegmatite where they formed (Larsen and Brooks, Journal of Petrology 35, 1994) and several metres across the magmatic stratigraphy would require unconsolidated cumulates i.e. a crystal mush. Geothermobarometric estimates from fluid inclusions, amphibole and feldspars show that the silica-rich aggregations solidified between 900 and 660 C at P from 1.8 to 2.9 kb. However, to be true products of liquid immiscibility they should form at T > 1050 C. With an average of 960 ppm Zr, the silica-rich aggregates are extremely Zr rich. Zr saturation thermometry imply minimum T's of 1070 (c. 2000 ppm Zr) to 900 C (c. 700 ppm Zr). Ti in Zr thermometry is progressing and may further constrain the T of formation. Although large uncertainties apply, a T of 1070 C or higher, would agree with a formation by liquid immiscibility. Assuming T > 1070 C the cumulus stratigraphy was unconsolidated with > 30 vol% intercumulus melts in the lower part of the magmachamber. With a density of 2.4-2.6 g/cm3, the silica-rich melts were much lighter than the ambient

  13. The East Greenland rifted volcanic margin

    Directory of Open Access Journals (Sweden)

    C. Kent Brooks

    2011-12-01

    Full Text Available The Palaeogene North Atlantic Igneous Province is among the largest igneous provinces in the world and this review of the East Greenland sector includes large amounts of information amassed since previous reviews around 1990.The main area of igneous rocks extends from Kangerlussuaq (c. 67°N to Scoresby Sund (c. 70°N, where basalts extend over c. 65 000 km2, with a second area from Hold with Hope (c. 73°N to Shannon (c. 75°N. In addition, the Ocean Drilling Project penetrated basalt at five sites off South-East Greenland. Up to 7 km thickness of basaltic lavas have been stratigraphically and chemically described and their ages determined. A wide spectrum of intrusions are clustered around Kangerlussuaq, Kialeeq (c. 66°N and Mesters Vig (c. 72°N. Layered gabbros are numerous (e.g. the Skaergaard and Kap Edvard Holm intrusions, as are under- and oversaturated syenites, besides small amounts of nephelinite-derived products, such as the Gardiner complex (c. 69°N with carbonatites and silicate rocks rich in melilite, perovskite etc. Felsic extrusive rocks are sparse. A single, sanidine-bearing tuff found over an extensive area of the North Atlantic is thought to be sourced from the Gardiner complex.The province is famous for its coast-parallel dyke swarm, analogous to the sheeted dyke swarm of ophiolites, its associated coastal flexure, and many other dyke swarms, commonly related to central intrusive complexes as in Iceland. The dyke swarms provide time markers, tracers of magmatic evolution and evidence of extensional events. A set of dykes with harzburgite nodules gives unique insight into the Archaean subcontinental lithosphere.Radiometric dating indicates extrusion of huge volumes of basalt over a short time interval, but the overall life of the province was prolonged, beginning with basaltic magmas at c. 60 Ma and continuing to the quartz porphyry stock at Malmbjerg (c. 72°N at c. 26 Ma. Indeed, activity was renewed in the Miocene with

  14. East Greenland Caledonides: stratigraphy, structure and geochronology: Lower Palaeozoic stratigraphy of the East Greenland Caledonides

    Directory of Open Access Journals (Sweden)

    Smith, M. Paul

    2004-12-01

    Full Text Available The Lower Palaeozoic stratigraphy of the East Greenland Caledonides, from the fjord region of North-East Greenland northwards to Kronprins Christian Land, is reviewed and a number of new lithostratigraphical units are proposed. The Slottet Formation (new is a Lower Cambrian quartzite unit, containing Skolithos burrows, that is present in the Målebjerg and Eleonore Sø tectonic windows, in the nunatak region of North-East Greenland. The unit is the source of common and often-reported glacial erratic boulders containing Skolithos that are distributed throughout the fjord region. The Målebjerg Formation (new overlies the Slottet Formation in the tectonic windows, and comprises limestones and dolostones of assumed Cambrian–Ordovician age. The Lower Palaeozoic succession of the fjord region of East Greenland (dominantly limestones and dolostones is formally placed in the Kong Oscar Fjord Group (new. Amendments are proposed for several existing units in the Kronprins Christian Land and Lambert Land areas, where they occur in autochthonous, parautochthonous and allochthonous settings.

  15. East Greenland Ridge in the North Atlantic Ocean

    DEFF Research Database (Denmark)

    Andreasen, Arne Døssing; Dahl-Jensen, T.; Thybo, Hans

    2008-01-01

    The combined Greenland-Senja Fracture Zones (GSFZ) represent a first-order plate tectonic feature in the North Atlantic Ocean. The GSFZ defines an abrupt change in the character of magnetic anomalies with well-defined seafloor spreading anomalies in the Greenland and Norwegian basins to the south...... but ambiguous and weak magnetic anomalies in the Boreas Basin to the north. Substantial uncertainty exists concerning the plate tectonic evolution of the latter area, including the role of the East Greenland Ridge, which is situated along the Greenland Fracture Zone. In 2002, a combined ocean-bottom seismometer...... and multichannel seismic (MCS) survey acquired two intersecting wide-angle reflection and coincident MCS profiles across and along the East Greenland Ridge. We present the results of integrated reflection seismic interpretation, first-arrival tomography, 2D kinematic raytracing, full-wave amplitude modeling...

  16. Luminescence dating of Late Quaternary sediments from East Greenland

    DEFF Research Database (Denmark)

    Mejdahl, V.; Funder, Svend Visby

    1994-01-01

    Luminescence dating based on K-feldspars and using both TL and OSL methods have been performed on 94 sediment samples from East Greenland. The ages go back more than 380 ka, but are mainly from the last interglaciation and the subsequent period and include both shallow-marine/coastal-fluvial and ......Luminescence dating based on K-feldspars and using both TL and OSL methods have been performed on 94 sediment samples from East Greenland. The ages go back more than 380 ka, but are mainly from the last interglaciation and the subsequent period and include both shallow...

  17. Luminescence dating of Late Quaternary sediments from East Greenland

    DEFF Research Database (Denmark)

    Mejdahl, V.; Funder, Svend Visby

    1994-01-01

    Luminescence dating based on K-feldspars and using both TL and OSL methods have been performed on 94 sediment samples from East Greenland. The ages go back more than 380 ka, but are mainly from the last interglaciation and the subsequent period and include both shallow-marine/coastal-fluvial and ......Luminescence dating based on K-feldspars and using both TL and OSL methods have been performed on 94 sediment samples from East Greenland. The ages go back more than 380 ka, but are mainly from the last interglaciation and the subsequent period and include both shallow...

  18. Recent changes in the freshwater composition east of Greenland

    NARCIS (Netherlands)

    de Steur, L.; Pickart, R.S.; Torres, D.J.; Valdimarsson, H.

    2015-01-01

    Results from three hydrographic surveys across the East Greenland Current between 2011 and 2013 are presented with focus on the freshwater sources. End-member analysis using salinity, d18O, and nutrient data shows that while meteoric water dominated the freshwater content, a significant amount of Pa

  19. First indication of Storegga tsunami deposits from East Greenland

    NARCIS (Netherlands)

    Wagner, B.; Bennike, O.; Klug, M.; Cremer, H.

    2007-01-01

    A 2.73 m long sediment sequence from Loon Lake, located at 18m a.s.l. on outer Geographical Society Ø, East Greenland, was investigated for its chronology and changes in physical and biogeochemical properties, macrofossils, and grain-size distribution. The predominance of marine fossils throughout t

  20. Age of the youngest Palaeogene flood basalts in East Greenland

    DEFF Research Database (Denmark)

    Heilmann-Clausen, C.; Piasecki, Stefan; Abrahamsen, Niels

    2008-01-01

    results, this constrains the termination of the East Greenland Paleogene Igneous Province to the Early-Middle Eocene transition (nannoplankton chronozones NP13-NP14/earliest NP15). This is 6-8 Ma younger than according to previous biostratigraphic age assignments. The new data show that flood basalt...

  1. Greenland Fracture Zone-East Greenland Ridge(s) revisited: Indications of a C22-change in plate motion?

    DEFF Research Database (Denmark)

    Døssing, Arne; Funck, T.

    2012-01-01

    Fracture Zone and separation of the 200-km-long, fracture-zone-parallel continental East Greenland Ridge from the Eurasia plate is thought to be related to a major change in relative plate motions between Greenland and Eurasia during the earliest Oligocene (Chron 13 time). This study presents...... a reinterpretation of the Greenland Fracture Zone -East Greenland Ridge based on new and existing geophysical data. Evidence is shown for two overstepping ridge segments (Segments A and B) of which Segment A corresponds to the already known East Greenland Ridge while Segment B was not detected previously....... Interpretation of sonobuoy data and revised modeling of existing OBS data across Segment B indicate a continental composition of the segment. This interpretation is supported by magnetic anomaly data. The Segments A and B are bounded by portions of the Greenland Fracture Zone with a distinct similar to 10...

  2. Fecundity of Greenland halibut (Reinhardtius hippoglossoides Walbaum) in East Greenland waters

    DEFF Research Database (Denmark)

    Gundersen, Agnes Christine; Rønneberg, Jan Erich; Boje, Jesper

    2001-01-01

    Fecundity is described for Greenland halibut, based on ovaries collected in July 1997 in ICES Division XIVb in East Greenland waters. The mean potential fecundity was estimated to be 113700 (range 32500–277100). Fecundity was significantly determined by total length. Fecundity–length and fecundity......–weight (round and gutted) relationships were estimated. Vitellogenic oocytes appearing dark in the microscope with a diameter ranging from 900 to 1650μm were counted and used in the fecundity estimates. This stage was easily distinguished from an early vitellogenic stage, with a diameter ranging from 490...

  3. Petroleum geological investigations in East greenland: project `Resources of the sedimentary basins of North and East Greenland`

    Energy Technology Data Exchange (ETDEWEB)

    Stemmerik, L.; Clausen, O.R.; Larsen, M.; Piasecki, S.; Therkelsen, J. [Geological Survey of Denmark and Greenland, Copenhagen (Denmark); Korstgaard, J. [Univ. of Aarhus, Geological Inst., Aarhus (Denmark); Seidler, L.; Surlyk, F. [Univ. of Copenhagen, Geological Inst., Copenhagen (Denmark)

    1997-12-31

    The multidisciplinary research project `Resources of the sedimentary basins of North and East Greenland` was initiated in 1995. The 1996 field work in East Greenland concentrated on integrated structural, sedimentological and biostratigraphical studies of the Upper Permian and Mesozoic successions. The most important new results arising from the 1996 field work are: 1) Re-interpretation of the Upper Permian Schuchert Dal Formation as a low stand turbidite unit within the Ravnefjeld Formation; 2) Recognition of Middle Jurassic deposits and thick lowermost Cretaceous sandstones on Hold with Hope; 3) Interpretation of a full spectrum of scarp-derived coarse-clastic mass movement deposits inter-bedded with Cretaceous shales on eastern Traill Oe; 4) The presence of a thick sand-rich Cretaceous turbidite succession on eastern Traill Oe; 5) Re-interpretation of the Mesozoic-Cenozoic fault systems on Traill Oe and Geographical Society Oe. (EG) 24 refs.

  4. Orogenic gold mineralisation hosted by Archaean basement rocks at Sortekap, Kangerlussuaq area, East Greenland

    Science.gov (United States)

    Holwell, D. A.; Jenkin, G. R. T.; Butterworth, K. G.; Abraham-James, T.; Boyce, A. J.

    2013-04-01

    A gold-bearing quartz vein system has been identified in Archaean basement rocks at Sortekap in the Kangerlussuaq region of east Greenland, 35 km north-northeast of the Skaergaard Intrusion. This constitutes the first recorded occurrence of Au mineralisation in the metamorphic basement rocks of east Greenland. The mineralisation can be classified as orogenic style, quartz vein-hosted Au mineralisation. Two vein types have been identified based on their alteration styles and the presence of Au mineralisation. Mineralised type 1 veins occur within sheared supracrustal units and are hosted by garnet-bearing amphibolites, with associated felsic and ultramafic intrusions. Gold is present as native Au and Au-rich electrum together with arsenopyrite and minor pyrite and chalcopyrite in thin alteration selvages in the immediate wall rocks. The alteration assemblage of actinolite-clinozoisite-muscovite-titanite-scheelite-arsenopyrite-pyrite is considered to be a greenschist facies assemblage. The timing of mineralisation is therefore interpreted as being later and separate event to the peak amphibolite facies metamorphism of the host rocks. Type 2 quartz veins are barren of mineralisation, lack significant alteration of the wall rocks and are considered to be later stage. Fluid inclusion microthermometry of the quartz reveals three separate fluids, including a high temperature ( T h = 300-350 °C), H2O-CO2-CH4 fluid present only in type 1 veins that in interpreted to be responsible for the main stage of Au deposition and sulphidic wall rock alteration. It is likely that the carbonic fluids were actually trapped at temperatures closer to 400 °C. Two other fluids were identified within both vein types, which comprise low temperature (100-200 °C) brines, with salinities of 13-25 wt% eq. NaCl and at least one generation of low salinity aqueous fluids. The sources and timings of the secondary fluids are currently equivocal but they may be related to the emplacement of

  5. Comparison of satellite imagery and infrared aerial photography as vegetation mapping methods in an arctic study area: Jameson Land, East Greenland

    DEFF Research Database (Denmark)

    Hansen, Birger Ulf; Mosbech, Anders

    1994-01-01

    Remote Sensing, vegetation mapping, SPOT, Landsat TM, aerial photography, Jameson Land, East Greenland......Remote Sensing, vegetation mapping, SPOT, Landsat TM, aerial photography, Jameson Land, East Greenland...

  6. The East Greenland Caledonides—teleseismic signature, gravity and isostasy

    DEFF Research Database (Denmark)

    Schiffer, Christian; Jacobsen, Bo Holm; Balling, Niels

    2015-01-01

    surrounding the North Atlantic. Teleseismic receiver function interpretation in the Central Fjord Region of East Greenland recently suggested the presence of a fossil Caledonian subduction complex, including a slab of eclogitised mafic crust and an overlying wedge of serpentinised mantle peridotite. Here we...... as a fossil subduction zone complex. The spatial relations with Caledonian structures suggest a Caledonian origin. The results indicate that topography is isostatically compensated by density variations within the lithosphere, and that significant dynamic topography is not required at the present day....

  7. Exploration history and place names of northern East Greenland: Colophon, abstract, introduction, official place names in Greenland

    Directory of Open Access Journals (Sweden)

    Higgins, Anthony K.

    2010-12-01

    Full Text Available The first recorded landing by Europeans on the coast of northern East Greenland (north of 69°N was that of William Scoresby Jr., a British whaler, in 1822. This volume includes a chronological summary of the pioneer 19th century exploration voyages made by British, Danish, Norwegian, Swedish, French and German expeditions – all of whom reported that the region had previously been occupied by the Inuit or Eskimo; also included are brief outlines of the increasing number of government and privately sponsored expeditions throughout the 20th century, whose objectives included cartography, geology, zoology, botany, trapping and the ascent of the highest mountain summits. In 1934 the Place Name Committee for Greenland was established, the tasks of which included a review of all place names hitherto recorded on published maps of Greenland, their formal adoption in danicised form, and the approval or rejection of new name proposals. In northern East Greenland, by far the largest numbers of new place names were those proposed by scientists associated with Lauge Koch’s geological expeditions that lasted from 1926 until 1958. This volume records the location and origin of more than 3000 officially approved place names as well as about 2650 unapproved names.The author’s interest in the exploration history and place names of northern East Greenland started in 1968, when the Geological Survey of Greenland initiated a major five-year geological mapping programme in the Scoresby Sund region. Systematic compilation of names began about 1970, initially with the names given by William Scoresby Jr., and subsequently broadened in scope to include the names proposed by all expeditions to northern East Greenland. The author has participated in 16 summer mapping expeditions with the Survey to northern East Greenland. Publication of this volume represents the culmination of a lifetime working in the Arctic.

  8. Solidification of interstitial melt in a gabbroic crystal mush: the Skaergaard intrusion, Greenland

    Science.gov (United States)

    Namur, Olivier; Humphreys, Madeleine C. S.; Holness, Marian B.; Veksler, Ilya V.

    2013-04-01

    The Eocene Skaergaard intrusion of East Greenland occupies a box-shaped, fault-bounded chamber, approximately 8km × 11km × 4km, at the contact between Precambrian gneisses and a thick overlying sequence of Eocene plateau lavas. The intrusion is divided into three main units: the Layered Series (LS) which crystallized on the floor, the Upper Border Series (UBS) which crystallized from the roof, and the Marginal Border Series (MBS) which grew inwards from the vertical walls. The order of appearance of cumulus phases in the LS is considered to be: plagioclase + olivine (HZ, LZa) + augite (LZb) + Fe-Ti oxides (LZc) - olivine (MZ) + olivine (UZa) + apatite (UZb) + ferro-hedenbergite (UZc). The Marginal Border Series (MBS) is subdivided in an analogous manner to the LS into HZ*, LZa*, LZb*, LZc*, MZ*, UZa* and UZb*. We measured plagioclase compositional profiles in the LS and MBS for major (EPMA) and trace (ion probe and LA-ICP-MS) elements. Plagioclase profiles in the MBS show a relatively simple pattern of continuously decreasing An-content from core to rim. Compatible trace elements evolve similarly to An, while incompatible trace elements continuously increase. In contrast, compositional profiles in the LS are highly complex. In the lowest stratrigraphic unit (LZa), the core of the plagioclase grains has a mantle of decreasing An-content with an external rim of constant composition at An55-58. Compatible and incompatible elements decrease and increase respectively from core to rim, signifying decoupling of major and trace elements in the external rim. In LZb, similar profiles are observed except that the external rim has a composition of An50-51. From LZc to UZa, plagioclase grains are mostly unzoned. However, where zoned they also show an external rim of constant composition, but this time at An40. From UZb to UZc, plagioclase grains are unzoned or show normal zoning without external constant composition rims. We suggest that the external rims at An58, An50 and An

  9. Estimates of reproductive potential of Greenland halibut (Reinhardtius hippoglossoides) in East Greenland based on an update of maturity status

    DEFF Research Database (Denmark)

    Kennedy, James; Hedeholm, Rasmus B.; Gundersen, Agnes C.

    2014-01-01

    ), respectively. Combining the maturity data with abundance data of Greenland halibut in East Greenland, spawning stock biomass (SSB) and total egg production (TEP) was estimated in four quadrants between 1998 and 2012 using both the previous and current interpretation of the maturity scale. Using the new...... interpretation of the scale led to a decrease in SSB estimates of 28–92% in specific areas and years, with an average of 56%. Estimates of TEP were directly proportional to SSB so this approach did not offer any advantages over SSB as a measure of reproductive potential. Length composition of Greenland halibut...

  10. Preliminary results of a geophysical study of the East Greenland Caledonides

    DEFF Research Database (Denmark)

    Schiffer, Christian; Jacobsen, B. H.; Balling, N.

    The present-day topography and crustal structure of the East Greenland Caledonides were intensively influenced by several constructive and destructive processes, including the Caledonian orogeny, the subsequent extensional collapse, continental breakup and fluvial and glacial erosional processes....

  11. Movements of female polar bears (Usrus maritimus) in the East Greenland pack ice

    DEFF Research Database (Denmark)

    Wiig, Øystein; Born, Erik W.; Pedersen, Leif Toudal

    2003-01-01

    The movements of two adult female polar bears (Ursus maritimus) in East Greenland and the Greenland Sea area were studied by use of satellite telemetry between the fall of 1994 and the summer of 1998. One female was tracked for 621 days, the other for 1,415 days. During this time the females used...... for a closer monitoring of the effects of this change on the East Greenland polar bear population....... movement rates varied between 0.32 and 0.76km/h. Both bears had very large home ranges (242,000 and 468,000 km(2)) within the dynamic pack ice of the Greenland Sea. The facts that the bears made extensive use of the offshore sea ice and that there is a marked reduction of the Greenland Sea ice call...

  12. Trace-element record in zircons during exhumation from UHP conditions, North-East Greenland Caledonides

    Science.gov (United States)

    McClelland, W.C.; Gilotti, J.A.; Mazdab, F.K.; Wooden, J.L.

    2009-01-01

    Coesite-bearing zircon formed at ultrahigh-pressure (UHP) conditions share general characteristics of eclogite-facies zircon with trace-element signatures characterized by depleted heavy rare earth elements (HREE), lack of an Eu anomaly, and low Th/ U ratios. Trace-element signatures of zircons from the Caledonian UHP terrane in North-East Greenland were used to examine the possible changes in signature with age during exhumation. Collection and interpretation of age and trace-element analyses of zircon from three samples of quartzofeldspathic gneiss and two leucocratic intrusions were guided by core vs. rim zoning patterns as imaged by cathodoluminesence. Change from igneous to eclogite-facies metamorphic trace-element signature in protolith zircon is characterized by gradual depletion of HREE, whereas newly formed metamorphic rims have flat HREE patterns and REE concentrations that are distinct from the recrystallized inherited cores. The signature associated with eclogite-facies metamorphic zircon is observed in coesite-bearing zircon formed at 358 ?? 4 Ma, metamorphic rims formed at 348 ?? 5 Ma during the initial stages of exhumation, and metamorphic rims formed at 337 ?? 5 Ma. Zircons from a garnet-bearing granite emplaced in the neck of an eclogite boudin and a leucocratic dike that cross-cuts amphibolite-facies structural fabrics have steeply sloping HREE patterns, variably developed negative Eu anomalies, and low Th/U ratios. The granite records initial decompression melting and exhumation at 347 ?? 2 Ma and later zircon rim growth at 329 ?? 5. The leucocratic dike was likely emplaced at amphibolite-facies conditions at 330 ?? 2 Ma, but records additional growth of compositionally similar zircon at 321 ??2 Ma. The difference between the trace-element signature of metamorphic zircon in the gneisses and in part coeval leucocratic intrusions indicates that the zircon signature varies as a function of lithology and context, thus enhancing its ability to aid in

  13. Last Interglacial (MIS5e) hydrographic shifts linked to meltwater discharges from the East Greenland margin

    Science.gov (United States)

    Zhuravleva, Anastasia; Bauch, Henning A.; Van Nieuwenhove, Nicolas

    2017-05-01

    Proximal evidence of the surface ocean response to size reduction of the Greenland Ice Sheet (GIS) during the Last Interglacial (MIS5e) and preceding glacial termination (T2) remains largely elusive. Using a new sediment record from the western Iceland Sea, the behavior of the northeastern GIS and its relation to the subpolar North Atlantic surface hydrography is examined. Extremely light oxygen isotopic (δ18O) values are found off central East Greenland during early MIS5e and point to enhanced meltwater release, potentially from the northeastern sector of the GIS. Data from downstream the cold East Greenland Current (EGC) and its eastward branches suggest a far-reaching effect of this meltwater not only in the Nordic Seas but also in the SE Labrador Sea. In particular, whereas an early MIS5e warming (at ∼128.5-126.5 ka) in the two regions coincided with the relative reduction of meltwater input into the EGC, the subsequent cooling noted at ∼126.5 ka followed a renewed major freshwater event off central East Greenland. Our data further indicate persistent freshwater influence from the East Greenland margin over the entire MIS5e interval and, in addition, also reveal a late MIS5e meltwater event. The latter event occurred just prior to the last glacial inception and emphasizes the importance of Greenland meltwater as forcing factor on Interglacial climates.

  14. From volcanic plains to glaciated peaks: Burial, uplift and exhumation history of southern East Greenland after opening of the NE Atlantic

    Science.gov (United States)

    Japsen, Peter; Green, Paul F.; Bonow, Johan M.; Nielsen, Troels F. D.; Chalmers, James A.

    2014-05-01

    In southern East Greenland (68-70°N), voluminous flood basalts erupted onto a largely horizontal lava plain near sea level at the Paleocene-Eocene transition when sea-floor spreading started in the NE Atlantic. Based on synthesis of geological observations, stratigraphic landform analysis and apatite fission-track analysis data in 90 rock samples, we show how three regional phases of uplift and exhumation subsequently shaped the present-day margin and controlled the discontinuous history of the Greenland ice sheet. A late Eocene phase of uplift led to formation of a regional erosion surface near sea level (the Upper Planation Surface, UPS). Uplift of the UPS in the late Miocene led to formation of the Lower Planation Surface (LPS) by incision below the uplifted UPS, and a Pliocene phase led to incision of valleys and fjords below the uplifted LPS, leaving mountain peaks reaching 3.7 km above sea level. Local uplift affected the Kangerlussuaq area (~ 68°N) during early Eocene emplacement of the Kangerlussuaq Intrusion and during late Oligocene block movements, that may be related to the detachment of the Jan Mayen microcontinent from Greenland, while middle Miocene thermal activity, coeval with lava eruptions, heated rocks along a prominent fault within the early Cretaceous to Paleocene Kangerlussuaq Basin. The three regional uplift phases are synchronous with phases in West Greenland, overlap in time with similar events in North America and Europe and also correlate with changes in plate motion. The much higher elevation of East Greenland compared to West Greenland suggests support in the east from the Iceland plume. These observations indicate a connection between mantle convection, changes in plate motion and vertical movements along passive continental margins.

  15. Investigating the potential for "water piracy" in North East Greenland

    Science.gov (United States)

    Karlsson, Nanna B.; Dahl-Jensen, Dorthe

    2013-04-01

    The incorporation of subglacial processes in ice flow models remains a challenge while at the same time observational evidence increasingly underscores the important role liquid water plays in ice flow dynamics. One of the many problems ice flow models face (that also includes scarcity of data at the bed and the deformational properties of water-saturated sediments) is the different time-scales on which the processes operate. For example, observations indicate that subglacial water may be re-routed to a neighbouring ice stream in response to changes in surface elevation. This implies that ice flow models have to allow for changes in ice flow mode where, depending on the basal properties, the flow may be dominated by deformation or basal sliding. The re-routing of water between neighbouring ice streams is often termed "water piracy" and in this study we demonstrate that the potential for water piracy exists even in regions with very small surface elevation changes. We use a simple, vertically integrated, 2D-plane ice flow model based on the shallow ice flow approximation to model the large-scale changes in surface elevation of North East Greenland in response to gravity and mass balance. Considering time-scales of 100-500 years the model predicts changes in elevation of less than a metre per year which is in agreement with data from remote sensing. We then calculate the corresponding changes in hydrological pressure potential and use evidence from radio-echo sounding data to identify areas with basal melting and thus potential liquid water production. The corresponding change in hydrological pressure potential in response to the surface elevation changes is sufficient to divert the subglacial water to different pathways. This change in subglacial water pathways could be sufficient to change the ice flow mode from deformation to sliding and might initiate speed-up and/or slow-down of the ice streams at the margins of the basin.

  16. Greenland

    Institute of Scientific and Technical Information of China (English)

    陈玮

    2002-01-01

    Greenland is the largest is land in the world.it is in the_____of Europe(欧洲)。Near Greenland is another island.it is small.its_____is lceland.do you think that greenland is green and warm? do you think that iceland is white with ice? if you do,you are______.

  17. Greenland

    DEFF Research Database (Denmark)

    Gad, Ulrik Pram

    2014-01-01

    The relationship between Greenland and the European Union (EU) can best be understood by exploring the development from Danish colonialism to a future independent Greenlandic state. In 1985, Greenland became the first territory ever to leave the European Economic Community (EEC) when it opted...... in 1979 and made the 1985 withdrawal possible. On 25 November 2008, a majority of the people of Greenland voted in favour of enhanced home rule – ‘self-government’ – still within formal Danish sovereignty. Denmark and Greenland alike are preparing for a future envisioned as involving climate change......, intensive raw material extraction, new transportation corridors and new claims to sovereignty over the Arctic. Greenland uses this imagined future as a way of enhancing its subjectivity, not the least when dealing with the EU. This article analyses how the Greenlandic self-understanding as being on the way...

  18. Petrogenesis of permian sulfide-bearing mafic-ultramafic intrusions insoutheast Chinese Altay and east Tianshan, NW China

    OpenAIRE

    Gao, Jianfeng; 高剑峰

    2012-01-01

    The Central Asia Orogenic Belt is one of the largest accretionary orogenic belts in the world. In this belt, many sulfide‐bearing mafic‐ultramafic intrusions occur along faults, including the Kalatongke complex in southeast Chinese Altay and the Huangshandong intrusion in east Tianshan. The Kalatongke complex is a composite body including ~308Ma dioritic intrusion and 287Ma sulfide‐bearing mafic intrusion. The dioritic intrusion consists of biotite‐hornblende gabbro, diorite and quartz d...

  19. Greenland

    DEFF Research Database (Denmark)

    Gad, Ulrik Pram

    2014-01-01

    The relationship between Greenland and the European Union (EU) can best be understood by exploring the development from Danish colonialism to a future independent Greenlandic state. In 1985, Greenland became the first territory ever to leave the European Economic Community (EEC) when it opted for....... On the other hand, the representation of the Greenland–EU relationship as one of sovereign equality – present and future – might just be able to provoke the resources necessary to make the dream come true....

  20. Bottom fish assemblages at the shelf and continental slope off East Greenland

    DEFF Research Database (Denmark)

    Jørgensen, Ole A; Hvingel, Carsten; Møller, P.R.

    2015-01-01

    During 2006 and 2008 two bottom trawl surveys were conducted at East Greenland to 72°N covering depths down to 1500 m. In the 149 trawl hauls in total 113 fish species were recorded of which 37 were considered pelagic and excluded from the analyses. As a first step the abundance data for the 76 b...

  1. Xenoendocrine pollutants May Reduce Size of Sexual Organs in East Greenland Polar Bears (Ursus Maritimus)

    DEFF Research Database (Denmark)

    Sonne, Christian; Leifsson, Pall S.; Dietz, Rune

    2006-01-01

    Reproductive organs from 55 male and 44 female East Greenland polar bears were examined to investigate the potential negative impact from organohalogen pollutants (OHCs). Multiple regressions normalizing for age showed a significant inverse relationship between OHCs and testis length and baculum ...

  2. A fossil subduction zone in the East Greenland Caledonides revealed by a Receiver Function analysis

    DEFF Research Database (Denmark)

    Schiffer, Christian; Jacobsen, B. H.; Balling, N.;

    evidence for the processes before and under the Caledonian orogeny. We performed a Receiver Function analysis of data from 11 seismological broadband stations forming the Ella-Øarray. This array, maintained by Aarhus University, covered an approximately 270 km long profile, spanning the East Greenland...

  3. Pb isotope evidence for contributions from different Iceland mantle components to Palaeogene East Greenland flood basalts

    DEFF Research Database (Denmark)

    Peate, David; Stecher, Ole

    2003-01-01

    We present new Pb isotope data on 21 samples of break-up-related flood basalts (56–54 Ma) from the Blosseville Kyst region of East Greenland. These samples show a considerable range in isotopic composition (206Pb/204Pb 17.6 to 19.3) that broadly correlates with compositional type. The ‘low-Ti’ type...

  4. Roughhead grenadier (Macrourus berglax) in the waters off East Greenland: Distribution and biology

    DEFF Research Database (Denmark)

    Fossen, Inge; Jørgensen, Ole A; Gundersen, Agnes C.

    2003-01-01

    The study focuses on distribution, catch rates and biological parameters of roughhead grenadier (Macrourus berglax) at East Greenland based on data from trawl surveys, longline surveys and commercial catches from the period 1994-2000. Roughhead grenadier was recorded at most fished stations...

  5. Geophysical investigations of the East Greenland Caledonides using receiver functions, gravity and topography data

    DEFF Research Database (Denmark)

    Schiffer, Christian; Balling, N.; Jacobsen, B. H.

    array crosses the East Greenland Caledonides from the ice sheet to the coastline at about 73 north. The data are of high quality. Initial Receiver Function results are interpreted together with corresponding gravity and topography data and additionally compared with synthetic data, using velocity models...

  6. Deshayesitid ammonites from the lower Aptian (Lower Cretaceous) of North-East Greenland

    NARCIS (Netherlands)

    Kelly, S.R.A.; Whitham, A.G.

    1999-01-01

    Two deshayesitid ammonite assemblages are described from the Lower Cretaceous succession of the north coast of Hold with Hope, North-East Greenland, and their biostratigraphical significance is assessed. In the earlier assemblage Prodeshayesites cf. bodei and P. laeviusculus occur. The second assemb

  7. PREVALENCE OF ANTIBODIES AGAINST TOXOPLASMA GONDII IN POLAR BEARS (URSUS MARITIMUS) FROM SVALBARD AND EAST GREENLAND

    Science.gov (United States)

    Serum samples from 419 polar bears (Ursus maritimus) from Svalbard and the Barents Sea (collected 1990 - 2000) and 108 polar bears from East Greenland (collected 1999 - 2004) were assayed for antibodies against Toxoplasma gondii using the modified agglutination test (MAT). Antibody prevalences were ...

  8. Bottom fish assemblages at the shelf and continental slope off East Greenland

    DEFF Research Database (Denmark)

    Jørgensen, Ole A; Hvingel, Carsten; Møller, P.R.

    2015-01-01

    During 2006 and 2008 two bottom trawl surveys were conducted at East Greenland to 72°N covering depths down to 1500 m. In the 149 trawl hauls in total 113 fish species were recorded of which 37 were considered pelagic and excluded from the analyses. As a first step the abundance data for the 76 b...

  9. Cenozoic burial and exhumation history of the Kangerlussuaq area, East Greenland, revealed by new apatite fission-track data

    Science.gov (United States)

    Japsen, Peter; Green, Paul F.; Bonow, Johan M.; Nielsen, Troels F.

    2010-05-01

    The Kangerlussuaq area in East Greenland (c. 68°N) has witnessed a complex geological development during the Cenozoic. The Skaergaard intrusion and the up to 5 km thick flood basalts formed during a short period around 55 Ma, and subsequently numerous intrusive bodies were emplaced, primarily during the Eocene. Relatively little is known about the geological history over the last 35 Myr, other than that an outlier of Middle Miocene lavas is located in the area at an elevation of c. 2.7 km. At the present-day, the area is deeply eroded and magmatic bodies that were emplaced deeply in the crust, are now exposed at the surface, but at the same time, the area has a significant elevation and even hosts the highest peak in Greenland, Gunbjørn Fjeld, 3.7 km above sea level. To unravel the history of burial and exhumation in the Kangerlussuaq area, new apatite fission-track analysis (AFTA) data has been acquired for 75 rock samples. Preliminary results show that the area has been subject to several phases of cooling since burial under the Palaeogene flood basalts. Phases of regional cooling along the coast that occurred at the Eocene-Oligocene transition and in the late Neogene are interpreted to be due to uplift and exhumation. Cooling events of local extent that occurred in the Eocene, Oligocene and Miocene are interpreted to be related to both exhumation and to circulating hot fluids. Results from samples along vertical transects reveal details of the protracted exhumation history, and that the present topography was formed during the late Neogene.

  10. Glacial evolution of Central-East Greenland Margin: a GLANAM project contribution

    Science.gov (United States)

    Pérez, Lara F.; Nielsen, Tove

    2017-04-01

    The dynamic evolution of the Greenland Ice Sheet is directly related to the Northern Hemisphere glaciation. The ice sheet has influenced the Greenland margins construction conditioning their morphology and their reply to other control factors in the evolution, as tectonic and oceanographic events. Thus, the sedimentary record preserved around Greenland has registered the glacial oscillations of the Northern Hemisphere, as well as the influence of other conditioning factors in the development of a permanent ice sheet on Greenland. The aim of this work is to summarize the new insights of Central-East Greenland glacial evolution reached within the framework of the Marie Curie Initial Training Network (ITN-FP7-PEOPLE-2012-ITN): Glaciated North Atlantic Margins (GLANAM) project. Several multichannel seismic profiles have been acquired along Central-East Greenland Margin, with both research and exploration proposes. They enable the large-scale reconstruction of the major stratigraphic events from late Miocene to Present, in agreement with an age correlation with ODP sites along the margin. High-resolution seismic, sub-bottom profiles, swath bathymetry and sediment cores are also locally available supporting detailed interpretation of the Quaternary sedimentary record. While ice-rafter debris (IRD) in the northern seas have been interpreted as indicators of tidewater glaciers on Greenland, the acoustic and seismic evidences summarized in this work allow reconstruction of different episodes of cross-shelf advances of the Greenland Ice Sheet along the central-east margin. The results of this work reveal an early cross-shelf glaciation occurred off Blosseville Kyst during late Miocene and early Pliocene followed by major ice-stream activity off Scoresby Sund during early Quaternary and glacial advance off Liverpool Land in late Quaternary. Higher resolution of the Quaternary data off Liverpool Land suggests that the intense ice-stream of the Scoresby Sund fjord was gradually

  11. Greenland

    DEFF Research Database (Denmark)

    Christoffersen, Lisbet

    2015-01-01

    the article includes updated informations regarding church-state relations in Greenland re the latest changes of the Church law......the article includes updated informations regarding church-state relations in Greenland re the latest changes of the Church law...

  12. A persistent and dynamic East Greenland Ice Sheet over the past 7.5 million years.

    Science.gov (United States)

    Bierman, Paul R; Shakun, Jeremy D; Corbett, Lee B; Zimmerman, Susan R; Rood, Dylan H

    2016-12-07

    Climate models show that ice-sheet melt will dominate sea-level rise over the coming centuries, but our understanding of ice-sheet variations before the last interglacial 125,000 years ago remains fragmentary. This is because terrestrial deposits of ancient glacial and interglacial periods are overrun and eroded by more recent glacial advances, and are therefore usually rare, isolated and poorly dated. In contrast, material shed almost continuously from continents is preserved as marine sediment that can be analysed to infer the time-varying state of major ice sheets. Here we show that the East Greenland Ice Sheet existed over the past 7.5 million years, as indicated by beryllium and aluminium isotopes ((10)Be and (26)Al) in quartz sand removed by deep, ongoing glacial erosion on land and deposited offshore in the marine sedimentary record. During the early Pleistocene epoch, ice cover in East Greenland was dynamic; in contrast, East Greenland was mostly ice-covered during the mid-to-late Pleistocene. The isotope record we present is consistent with distinct signatures of changes in ice sheet behaviour coincident with major climate transitions. Although our data are continuous, they are from low-deposition-rate sites and sourced only from East Greenland. Consequently, the signal of extensive deglaciation during short, intense interglacials could be missed or blurred, and we cannot distinguish between a remnant ice sheet in the East Greenland highlands and a diminished continent-wide ice sheet. A clearer constraint on the behaviour of the ice sheet during past and, ultimately, future interglacial warmth could be produced by (10)Be and (26)Al records from a coring site with a higher deposition rate. Nonetheless, our analysis challenges the possibility of complete and extended deglaciation over the past several million years.

  13. A persistent and dynamic East Greenland Ice Sheet over the past 7.5 million years

    Science.gov (United States)

    Bierman, Paul R.; Shakun, Jeremy D.; Corbett, Lee B.; Zimmerman, Susan R.; Rood, Dylan H.

    2016-12-01

    Climate models show that ice-sheet melt will dominate sea-level rise over the coming centuries, but our understanding of ice-sheet variations before the last interglacial 125,000 years ago remains fragmentary. This is because terrestrial deposits of ancient glacial and interglacial periods are overrun and eroded by more recent glacial advances, and are therefore usually rare, isolated and poorly dated. In contrast, material shed almost continuously from continents is preserved as marine sediment that can be analysed to infer the time-varying state of major ice sheets. Here we show that the East Greenland Ice Sheet existed over the past 7.5 million years, as indicated by beryllium and aluminium isotopes (10Be and 26Al) in quartz sand removed by deep, ongoing glacial erosion on land and deposited offshore in the marine sedimentary record. During the early Pleistocene epoch, ice cover in East Greenland was dynamic; in contrast, East Greenland was mostly ice-covered during the mid-to-late Pleistocene. The isotope record we present is consistent with distinct signatures of changes in ice sheet behaviour coincident with major climate transitions. Although our data are continuous, they are from low-deposition-rate sites and sourced only from East Greenland. Consequently, the signal of extensive deglaciation during short, intense interglacials could be missed or blurred, and we cannot distinguish between a remnant ice sheet in the East Greenland highlands and a diminished continent-wide ice sheet. A clearer constraint on the behaviour of the ice sheet during past and, ultimately, future interglacial warmth could be produced by 10Be and 26Al records from a coring site with a higher deposition rate. Nonetheless, our analysis challenges the possibility of complete and extended deglaciation over the past several million years.

  14. The East Greenland Caledonides from the viewpoint of Receiver Functions, gravity and topography data

    DEFF Research Database (Denmark)

    Schiffer, Christian; Balling, N.; Jacobsen, B. H.;

    and the subsequent major collision and orogeny (420 Ma) the Caledonian deformation included several early stages of terrain accretion along the involved continents [1]. The high topographic elevation in the Caledonides and its longevity attract special attention, but also shallow extensional features, a lower...... to 2011) 11 temporary broadband stations were deployed and maintained by Aarhus University, forming the approximately 270 km long Ella-Ø-array. The profile extends from the Greenland ice sheet to the coastline, crossing the East Greenland Caledonides at about 73° north. The data are of high quality. P...

  15. Size and density of East Greenland polar bear (Ursus maritimus) skulls

    DEFF Research Database (Denmark)

    Sonne, C.; Bechshøft, T.O.; Rigét, F.F.

    2013-01-01

    density (BMD) in 87 East Greenland male polar bears (Ursus maritimus) sampled in the time period of 1892-2010. The purpose of the study was to investigate if these measures are potential candidates as indicators for stress associated with climate change and long-range transported toxic industrial...... chemicals. The analyses showed that both BMD and CBL in polar bears sampled in period 4 (1999-2010, n = 57) were significantly lower when compared with period 2 (1920-1936, n = 19) (both p ... that BMD and body size have decreased in East Greenland polar bear males over the past 120 years and that exposure to organohalogen contaminants may explain the BMD reductions. It is, however, not entirely clear if and how climatic oscillations affected the reductions in body size and BMD mainly because...

  16. Formation of source and reservoir rocks in a sequence stratigraphic framework Jameson Land East Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Piasecki, S.; Dam, G.; Hansen, C.F.; Koppelhus, E.B.; Stemmerik, L.; Surlyk, F.

    1996-12-31

    Sedimentological, biostratigraphical and sequence stratigraphical analyses of East Greenland sedimentary successions with significant source and reservoir qualities have resulted in a major increase in the understanding of their depositional conditions, distribution and geometry`s. A biostratigraphical scheme of the Jurassic succession based on spores, pollen and dinoflaggelate cyst has been constructed for correlation and dating of the very detailed sequence stratigraphical units across the North Atlantic Ocean. Middle and Upper Jurassic dinoflaggelate stratigraphy is closely correlated to Boreal ammonite stratigraphy and deviations from the NW-European standard dinocyst stratigraphy have been recorded. The Upper Permian Folvik Creek Group was deposited in a marine, carbonate-dominated depositional system under arid climatic conditions. The organic-rich shales of the Ravnefjeld Formation represents highstand systems tracts. Reservoir rocks were formed by secondary dissolution of carbonates which were exposed during low relativ sea-level and as sandy turbidites deposited in lowstand systems tract. The uppermost Triassic - lowermost Jurassic Kap Stewart Group was deposited in a large rift lake. Organic-rich shales were deposited distally during lake level highstand. Deltaic reservoir sandstones were deposited in lowstand systems tracts as a respond to forced regressin induced by rapid variations in relative lake-level. The overlying marine Jurassic deposits include several sandstone units with reservoir potential representing both lowstand and high stand systems tracts. The organic rich mudstones were only developed as potential source rocks for oil when the deposition was combined with high marine organic production and basinal anoxic conditions e.g. during deposition of the Middle Jurassic Sortehat Formation and the Upper Jurassic Hareelv Formations. Several of the largestloilfields in the North Sea and on the Norwegian shelf have close analogues in the Jurassic

  17. Formation of source and reservoir rocks in a sequence stratigraphic framework Jameson Land East Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Piasecki, S.; Dam, G.; Hansen, C.F.; Koppelhus, E.B.; Stemmerik, L.; Surlyk, F.

    1996-12-31

    Sedimentological, biostratigraphical and sequence stratigraphical analyses of East Greenland sedimentary successions with significant source and reservoir qualities have resulted in a major increase in the understanding of their depositional conditions, distribution and geometry`s. A biostratigraphical scheme of the Jurassic succession based on spores, pollen and dinoflaggelate cyst has been constructed for correlation and dating of the very detailed sequence stratigraphical units across the North Atlantic Ocean. Middle and Upper Jurassic dinoflaggelate stratigraphy is closely correlated to Boreal ammonite stratigraphy and deviations from the NW-European standard dinocyst stratigraphy have been recorded. The Upper Permian Folvik Creek Group was deposited in a marine, carbonate-dominated depositional system under arid climatic conditions. The organic-rich shales of the Ravnefjeld Formation represents highstand systems tracts. Reservoir rocks were formed by secondary dissolution of carbonates which were exposed during low relativ sea-level and as sandy turbidites deposited in lowstand systems tract. The uppermost Triassic - lowermost Jurassic Kap Stewart Group was deposited in a large rift lake. Organic-rich shales were deposited distally during lake level highstand. Deltaic reservoir sandstones were deposited in lowstand systems tracts as a respond to forced regressin induced by rapid variations in relative lake-level. The overlying marine Jurassic deposits include several sandstone units with reservoir potential representing both lowstand and high stand systems tracts. The organic rich mudstones were only developed as potential source rocks for oil when the deposition was combined with high marine organic production and basinal anoxic conditions e.g. during deposition of the Middle Jurassic Sortehat Formation and the Upper Jurassic Hareelv Formations. Several of the largest oilfields in the North Sea and on the Norwegian shelf have close analogues in the Jurassic

  18. Glacial flutings in bedrock, an observation in East Greenland

    DEFF Research Database (Denmark)

    Funder, Svend Visby

    1978-01-01

    Large scale glacial flutings cover an area of 4 x 1.5 km on the northern shore of Harefjord in the interior Scoresby Sund fjord complex. The flutings are modelled in coarse sandstone and conglomerates, a few small features are probably composed of till. The ridges measure up to' 2000 m in length...... and 5 m in height and occur between 50 and 250 m above sea level inthe gently sloping lowland area adjacent to the fjord. They were probably formed beneath the lateral part of the former Harefjord-Glacier which receded rapidly in the fjord and exposed the area at c. 7500 years BP. Large scale glacial...... flutings have not been recorded before in Greenland, but seem to be of common occurrence in parts of North America. They have probably been formed near the margin of actively moving glaciers, and secondary flow in the basal ice may have played an important role...

  19. Late Permian carbonate concretions in the marine siliciclastic sediments of the Ravnefjeld Formation, East Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, J.K. [Univ. of Copenhagen, Geological Inst., Copenhagen (Denmark); Hanken, N.M. [Univ. of Tromsoe, Dept. of Geology, Tromsoe (Norway)

    2002-07-01

    The investigation of carbonate concretions from the Late Permian Ravnefjeld Formation in East Greenland forms part of the multi-disciplinary research project Research of the Sedimentary Basins of North and East Greenland (TUPOLAR). The TUPOLAR project focuses on investigations and evaluation of potential hydrocarbon and mineral resources of the Upper Permian - Mesozoic sedimentary basins. In this context, the Upper Permian Ravnefjeld Formation occupies a pivotal position because it contains local mineralization and has source rock potential for hydrocarbons adjacent to potential carbonate reservoir rocks of the partly time-equivalent Wegener Halvoe Formation. A better understanding of the sedimentary facies and diagenesis of the Ravnefjeld Formation is therefore crucial for an evaluation of the economic evaluation of East Greenland. The original fieldwork was carried out in 1998, when sampling was undertaken of representative carbonate concretions and surrounding beds from a limited number of well-exposed sections in the Ravnefjeld Formation. The sampled material was subsequently investigated by a combination of petrography and stable isotope chemistry to decipher the relationships between the diagenetic development of the carbonate concretions and the mineralization in the sequence. The sequential precipitation of the cement generations was analysed in cement-filled primary voids in gastropods because these showed the most complete development of the different cement generations. The geochemistry of stable isotopes was also studied. During the petrographic work, we became aware of a hitherto unrecognised biota dominated by calcispheres. The well-developed cement generations in primary cavities in skeletal material were used to elucidate the diagenesis. (BA)

  20. Quotas on narwhal (Monodon monoceros) hunting in East Greenland

    DEFF Research Database (Denmark)

    Nielsen, Martin Reinhardt; Meilby, Henrik

    2013-01-01

    This study evaluates the introduction of quotas on narwhal hunting in East Greenland with respect to effects on Inuit culture and based on trends in narwhal killed per hunter and assessment of migration patterns. Cultural aspects were assessed through group discussions and comparison between East....../hunter; and suggest southwest- bound migration, implying potential immigration from non-hunted populations that was not considered in quota setting. The implementation of quotas without local consultations and legal basis in the relevant executive order is therefore in our opinion inappropriate. Conservation...

  1. Oceanic heat delivery via Kangerdlugssuaq Fjord to the south-east Greenland ice sheet

    Science.gov (United States)

    Inall, Mark E.; Murray, Tavi; Cottier, Finlo R.; Scharrer, Kilian; Boyd, Timothy J.; Heywood, Karen J.; Bevan, Suzanne L.

    2014-02-01

    Acceleration of the Greenland Ice Sheet (GrIS) tidewater outlet glaciers has increased the ice sheet's contribution to global sea level rise over the last two decades. Coincident increases in atmospheric temperatures around Greenland explain some of the increased ice loss, but warm Atlantic-origin water (AW) is increasingly recognized as contributing to the accelerating ice-mass loss, particularly, via the outlet glaciers of south-east (SE) Greenland. However, there remains a lack of understanding of the variability in heat content of the water masses found to the east of Greenland and how this heat is communicated to the outlet glaciers of the GrIS. Here a new analysis is presented of ocean/GrIS interaction in which the oceanic heat flux toward the ice sheet in Kangerdlugssuaq Fjord (0.26 TW) is an order-of-magnitude greater than that reported for the other major outlet glacier of SE Greenland (Helheim). Heat delivered by AW to the calving front of Kangerdlugssuaq is equivalent to ˜10 m d-1 melt (i.e., 30-60% of the ice flow speed), and thus is highly significant. During the observational campaign in September 2010 warm Polar Surface Water (PSWw) melted a substantial volume of ice within the fjord; equivalent to 25% of the volume melted by AW alone. Satellite-derived sea surface temperatures show large interannual variability in PSWw over the 20 year period 1991-2011. Anomalously warm PSWw was observed within the fjord prior to the well-documented major ice front retreats of May 2004 and November 2010.

  2. East Greenland flood basalt volcanism: duration, volatile flux and correlation to the Paleocene-Eocene thermal maximum

    Science.gov (United States)

    Tegner, C.; Heilmann-Clausen, C.; Larsen, R. B.; Kent, A. J. R.

    2012-04-01

    Massive flood basalt volcanism in the NE Atlantic 56 million years ago can be related to the initial manifestation of the Iceland plume and ensuing continental rifting, and has been correlated with a short (c. 200,000 years) global warming period, the Paleocene-Eocene thermal maximum (PETM). A hypothesis is that magmatic sills emplaced into organic-rich sediments on the Norwegian margin triggered rapid release of greenhouse gases. However, the largest exposed volcanic succession in the region, the E Greenland flood basalts provide additional details. The alkaline Ash-17 provides regional correlation of continental volcanism and pertubation of the oceanic environment. In E Greenland Ash-17 is interbedded with the uppermost part of the flood basalt succession. In the marine sections of Denmark, Ash-17 postdates PETM, most likely by 3-400,000 years. While radiometric ages bracket the duration of the main flood basalt event to less than a million years, the subsidence history of the Skaergaard intrusion due to flood basalt emplacement indicates it took less than 300,000 years. It is therefore possible that the main flood basalts in E Greenland postdates PETM. This is supported by a scarcity of ash layers within the PETM interval. Continental flood basalt provinces represent some of the highest sustained volcanic outputs preserved within the geologic record. Recent studies have focused on estimating the atmospheric loading of volatile elements and have led to the suggestion that they may be associated with significant global climate changes and mass extinctions. Estimates suggest that c. 400,000 km3 of basaltic lava erupted in E Greenland and the Faeroe islands. Based on measurements of melt inclusions and solubility models, approximately 3000 Gt of SO2 and 220 Gt of HCl were released by these basalts. Calculated yearly fluxes approach 10 Mt/y SO2 and 0.7 Mt/y HCl. Refinements of these estimates, based largely on further melt inclusion measurements, are proceeding. Our

  3. Historical ablation rates on south-east Greenland glaciers measured in the 1933 warm summer

    Directory of Open Access Journals (Sweden)

    Bent Hasholt

    2016-07-01

    Full Text Available Ice ablation rates measured on four glaciers in south-east Greenland in summer 1933 are recovered from an old field book of geologist K. Milthers. These unpublished ablation data are among the first measured in Greenland and were obtained during a warm period comparable to that of recent years. Ablation rates of up to 45 mm ice eq. d−1 were observed. Using the Tasiilaq meteorological record, we calculate degree-day factors of ca. 3–5 mm ice eq. d−1°C−1. Comparing these results with 1996–2012 observations at one of Milthers’ glaciers (Mittivakkat, we find that ablation rates and degree-day factors are significantly higher (61±50% in recent years. We speculate this to be due to a reduction in surface albedo, and perhaps the retreat of the glaciers out of the cold maritime inversion layer. Our findings suggest that using a temperature-index method that assumes constant degree-day factors may produce inaccurate long-term ablation estimates for south-east Greenland glaciers, further emphasizing the value of the rare 1933 measurements for validation of ablation models.

  4. Changes in the marine-terminating glaciers of central east Greenland, 2000–2010

    Directory of Open Access Journals (Sweden)

    K. M. Walsh

    2012-02-01

    Full Text Available Marine-terminating outlet glaciers of the Greenland Ice Sheet have undergone substantial changes over the past decade. The synchronicity of these changes suggest a regional external forcing, such as changes in coastal ocean heat transport and/or increased surface melt and subglacial runoff. A distinct contrast in rates of ice front retreat has been observed between glaciers north and south of 69° N latitude on along the East Greenland coast. This latitude corresponds with the northward limit of subtropical waters carried by the Irminger Current, suggesting variability in ocean heat transport as the dominant forcing. Glacier surging, however, is yet another mechanism of change in this region. In order to provide further spatial and temporal constraint on glacier change across this important oceanographic transition zone, we construct time series of thinning, retreat and flow speed of 37 marine-terminating glaciers along the central east Greenland coast from 2000 to 2010. We assess this dataset for spatial and temporal patterns that may elucidate the mechanisms of glacier change. We confirm that glacial retreat, dynamical thinning, and acceleration have been more pronounced south of 69° N, with a high degree of variability along the Blosseville Coast and little inter-annual change in Scoresby Sound. Our results support the conclusion that variability in coastal ocean heat transport is the primary driver of regional glacier change, but that local factors, such as surging and/or individual glacier morphology, are overprinted on this regional signal.

  5. No Abrupt Changes in redox conditions associated with the end-Permian marine ecosystem collapse in the east Greenland basin

    DEFF Research Database (Denmark)

    Nielsen, Jesper K.; Shen, Y; Piasecki, Stefan

    2010-01-01

    compositions of pyrites from the East Greenland Basin. The size distributions of framboidal pyrites in sediments from a continuous section across the Permian–Triassic boundary reveal that sulfidic conditions in water columns were established about 0.7 m above the extinction event in the East Greenland Basin...... is not indicative of an abrupt change of redox chemistry in water columns, in contrast to previous claims. The integration of isotope and framboidal pyrite data provides a nearly continuous record of ocean chemistry evolution and new insights into the end-Permian extinction and delayed biotic recovery in the East...

  6. Spatial and temporal melt variability at Helheim Glacier, East Greenland, and its effect on ice dynamics

    DEFF Research Database (Denmark)

    Andersen, M. L.; Larsen, T. B.; Nettles, M.

    2010-01-01

    Understanding the behavior of large outlet glaciers draining the Greenland Ice Sheet is critical for assessing the impact of climate change on sea level rise. The flow of marine-terminating outlet glaciers is partly governed by calving-related processes taking place at the terminus but is also...... influenced by the drainage of surface runoff to the bed through moulins, cracks, and other pathways. To investigate the extent of the latter effect, we develop a distributed surface-energy-balance model for Helheim Glacier, East Greenland, to calculate surface melt and thereby estimate runoff. The model...... is driven by data from an automatic weather station operated on the glacier during the summers of 2007 and 2008, and calibrated with independent measurements of ablation. Modeled melt varies over the deployment period by as much as 68% relative to the mean, with melt rates approximately 77% higher...

  7. The nature and genesis of marginal Cu-PGE-Au sulphide mineralisation in Paleogene Macrodykes of the Kangerlussuaq region, East Greenland

    Science.gov (United States)

    Holwell, David A.; Abraham-James, Thomas; Keays, Reid R.; Boyce, Adrian J.

    2012-01-01

    The Kangerlussuaq region of East Greenland hosts a variety of early Tertiary extrusive and intrusive igneous rocks related to continental break up and the passage of the ancestral Iceland plume. These intrusive bodies include a number of gabbroic macrodykes, two of which—the Miki Fjord Macrodyke, and the newly discovered Togeda Macrodyke—contain Cu-PGE-Au sulphide mineralisation along their margins. Sulphides occur as disseminated interstitial blebs and rounded globules of chalcopyrite and pyrrhotite with some Fe-Ti oxides and platinum-group minerals, comprising largely Pd bismuthides and tellurides. The globules are interpreted to have formed from fractionation of trapped droplets of an immiscible Cu- and Pd-rich sulphide melt and show geopetal indicators. Sulphur isotopes imply a local crustal source of S in these from pyritic sediments of the Kangerlussuaq Basin. Thus, generation of these sulphide occurrences was controlled by local country rock type. Low Ni/Cu and Pt/Pd ratios, also present in the Platinova reefs in the Skaergaard Intrusion, indicate that early fractionation of olivine may have depleted the magma of Ni and suggest the likely presence of a large magma chamber at depth. Xenoliths of Ni-rich olivine cumulates in the Miki Fjord Macrodyke may have been sourced from such a body. The location of thus far unidentified conduit or feeder zones to the macrodykes beneath the present day surface may represent potential targets for more massive sulphide orebodies.

  8. Oceanographic Data from Northwest Greenland Sea: Arctic East 1979 Survey of the USCGC Westwind.

    Science.gov (United States)

    1981-01-01

    AD-A091 80 SCIENCE APPLICATIONS INC LA JOLLA CA F/6 A/10 OCEANOGRAPHIC DATA FROM NORTHWEST GREENLAND SEA: ARCTIC EAST 19--ETC(U) IW81 J L NEWTON . L E...PIPER NOOOIA-79-C-0689 NCLASSIFIED SAI-202-81I03"LJ NL 3EIIEEE IEEE, mmmmhhIIIIIIu LEYE V scewce AppIcloNs IKEic Si3 23 064 r/£SAT -81- 3-L3...in the scientific group were: Dr. John L. Newton , Science Applications, Inc., La Jolla, CA Chief Scientist Mr. Lee Piper, Science Applications, Inc

  9. Sedimentology and distribution of Upper Permian lowstand fans, Bredehorn Member, Schuchert Dal Formation, East Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Kreiner-Moeller, M.; Piasecki, S.; Stemmerik, L.

    1999-07-01

    The Upper Permian basin of central East Greenland was characterized by shallow marine platform carbonates along the basin margins and over fault crests, and deeper water siliciclastics in the basin centres during the later stages of deposition. The basinal, siliciclastic-dominated succession includes the organic rich, source prone shales of the Ravnefjeld Formation and sandy and silty sediments of the Schuchert Dal Formation. The traditional view of these formations is that they represent discrete stages of basin evolution. However, renewed fieldwork indicates that the lower part of the sandy Bredehorn Member of the Schuchert Dal Formation is time equivalent to the upper part of the Ravnefjeld Formation. The presentation discusses the details.

  10. Is bone mineral composition disrupted by organochlorines in east Greenland polar bears (Ursus maritimus)?

    DEFF Research Database (Denmark)

    Sonne, Christian; Dietz, Rune; Born, Erik W;

    2004-01-01

    ), dichlorodiphenyl trichloroethane (DDT) and its metabolites, chlordanes (CHLs), dieldrin, hexacyclohexanes, hexachlorobenzene] and polybrominated diphenyl ether (PBDE) compounds. To ensure that the BMD value in skull represented the mineral status of the skeletal system in general, we compared BMD values in femur...... and three lumbar vertebrae with skull in a subsample. We detected highly significant correlations between BMD in skull and femur (r = 0.99; p PBDE period (1892.......04) and SigmaCHL (p PBDE in subadults were also found (p = 0.06). In conclusion, the strong correlative relationships suggest that disruption of the bone mineral composition in East Greenland polar...

  11. The subfossil occurrence of Mytilus edulis L. in central East Greenland

    DEFF Research Database (Denmark)

    Hjort, Christian; Funder, Svend Visby

    1974-01-01

    The subfossil occurrence of Mytilus edulis in central East Greenland has been CH-dated to roughly between 8000 B.P. and 5500 B.P.; compared with other areas this is a short period. Its immigration coincides with the final deglaciation of the innermost fjords, and its disappearance is contemporane...... islandica can or could live, even if this was not possible along the surrounding and more hostile outer coasts. The reason for the absence of Mytilus edulis from the region today is probably not the local climate....

  12. Geologic Assessment of Undiscovered Oil and Gas Resources of the West Greenland-East Canada Province

    Science.gov (United States)

    Schenk, Christopher J.

    2010-01-01

    The U.S. Geological Survey (USGS) recently assessed the potential for undiscovered oil and gas resources of the West Greenland-East Canada Province as part of the USGS Circum-Arctic Resource Appraisal program. The province lies in the offshore area between western Greenland and eastern Canada and includes Baffin Bay, Davis Strait, Lancaster Sound, and Nares Strait west of and including part of Kane Basin. A series of major tectonic events led to the formation of several distinct structural domains that are the geologic basis for defining five assessment units (AU) in the province, all of which are within the Mesozoic-Cenozoic Composite Total Petroleum System (TPS). Potential petroleum source rocks within the TPS include strata of Ordovician, Early and Late Cretaceous, and Paleogene ages. The five AUs defined for this study-the Eurekan Structures AU, Northwest Greenland Rifted Margin AU, Northeast Canada Rifted Margin AU, Baffin Bay Basin AU, and the Greater Ungava Fault Zone AU-encompass the entire province and were assessed for undiscovered, technically recoverable resources.

  13. Skull pathology in East Greenland and Svalbard polar bears (Ursus maritimus) during 1892 to 2002 in relation to organochlorine pollution

    Energy Technology Data Exchange (ETDEWEB)

    Sonne, Christian [National Environmental Research Institute, Department of Arctic Environment, Frederiksborgvej 399, DK-4000 Roskilde (Denmark) and Department of Veterinary Basic Sciences, Royal Veterinary and Agricultural University, Buelowsvej 17, DK-1870 Frederiksberg C (Denmark)]. E-mail: csh@dmu.dk; Riget, Frank F. [National Environmental Research Institute, Department of Arctic Environment, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Dietz, Rune [National Environmental Research Institute, Department of Arctic Environment, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Wiig, Oystein [Natural History Museum, University of Oslo, PO Box 1172 Blindern, N-0562 Oslo (Norway); Kirkegaard, Maja [National Environmental Research Institute, Department of Arctic Environment, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Born, Erik W. [Greenland Institute of Natural Resources, PO Box 570, DK-3900 Nuuk, Greenland (Denmark)

    2007-01-01

    East Greenland and Svalbard polar bears (Ursus maritimus) are heavily polluted with long-range transported organochlorines such as PCBs (polychlorinated biphenyls). To investigate the negative health impacts, a time-trend study of skull pathology was conducted on 269 East Greenland and 241 Svalbard polar bears. The skulls were sampled during 1892-2002 and 1964-1992, respectively. Seven different pathological changes were found: adonti, displacement of teeth, caries, osseous proliferations, exostosis, tooth wear and periodontitis. Only tooth wear and periodontitis was in a prevalence that allowed statistical treatment. The most severe cases of tooth wear and periodontitis were accompanied by a substantial loss of alveolar bone structure. The prevalence of tooth wear and periodontitis increased significantly with age (p < 0.001) with incisor wear being more severe than in canines, premolars and molars (p < 0.001). No sex difference was found for tooth wear (p = 0.22) while a significant difference between sexes was found for periodontitis (p = 0.01) with males having higher prevalence than females (odds ratio of 2.5 for males:females). In East Greenland, the prevalence of tooth wear was significantly higher in polar bears collected in the pre pollution period (< 1960) than in bears sampled during polluted periods (1960-1980 and 1981-2002) (p < 0.001). Regarding periodontitis, the prevalence was not significantly different between pre-pollution and pollution periods (p = 0.309). Polar bears from Svalbard had significantly higher prevalence of tooth wear (p < 0.001) and periodontitis (p = 0.02) than polar bears from East Greenland. The tooth wear and periodontitis odds ratios for Svalbard:East Greenland were 135 and 2.6, respectively. Hence, we found a clear age/sex link and geographical difference but no evidence for an association between skull pathology and exposure to organochlorines in East Greenland and Svalbard polar bears.

  14. Ice-water vortex at the edge of the East Greenland current

    Energy Technology Data Exchange (ETDEWEB)

    Wadhams, P.; Squire, V.A.

    1983-03-30

    During the Ymer-80 cruise in August 1980 we observed an ice feature of 60-km diameter having the shape of a breaking wave. It lay at the edge of the East Greenland drift ice in Fram Strait with its center at 79/sup 0/15'N, 00/sup 0/38'E, and the wave was breaking upstream relative to the East Greenland current. Two conductivity, temperature, and depth sections across the feature in N-S and E-W directions revealed warm (up to 4.3 C) water some 60 km inside the polar front, in lenses centered at 40-m depth but with an effect to beyond 600 m. The temperature anomalies were accompanied by salinity anomalies so that there was little net effect on the density profile. The form of the sections, together with the ice distribution (observed by vertical photography from a helicopter) and surface motion (observed by tracking four radar transponders) all suggest that the feature is a vortex produced by an instability in the polar front. It has similar characteristics to vortices investigated experimentally and theoretically by Griffiths and Linden (1981a, b, 1982) and observationally by Wadhams et al. (1979).

  15. An ice-water vortex at the edge of the East Greenland Current

    Science.gov (United States)

    Wadhams, P.; Squire, V. A.

    1983-03-01

    During the Y mer-80 cruise in August 1980 we observed an ice feature of 60-km diameter having the shape of a breaking wave. It lay at the edge of the East Greenland drift ice in Fram Strait with its center at 79°15'N, 00°38'E, and the wave was breaking upstream relative to the East Greenland Current. Two conductivity, temperature, and depth sections across the feature in N-S and E-W directions revealed warm (up to 4.3°C) water some 60 km inside the polar front, in lenses centered at 40-m depth but with an effect to beyond 600 m. The temperature anomalies were accompanied by salinity anomalies so that there was little net effect on the density profile. The form of the sections, together with the ice distribution (observed by vertical photography from a helicopter) and surface motion (observed by tracking four radar transponders) all suggest that the feature is a vortex produced by an instability in the polar front. It has similar characteristics to vortices investigated experimentally and theoretically by Griffiths and Linden (1981a, b, 1982) and observationally by Wadhams et al. (1979).

  16. Last Interglacial (MIS5e) hydrographic shifts linked to meltwater discharges from the East Greenland margin

    Science.gov (United States)

    Zhuravleva, Anastasia; Bauch, Henning A.; Van Nieuwenhove, Nicolas

    2016-04-01

    The East Greenland Current (EGC) plays a key role in transporting polar water from the Arctic to convectional sites of the Iceland and Labrador seas. Ongoing melting of the Greenland Ice Sheet (GIS) as well as the Arctic sea ice prompts freshening of the EGC and accumulation of low-density water in the subpolar North Atlantic, thus affecting the stabilities of water mass overturning and subsequent northward heat transfer. To assess natural eastern GIS dynamics and possible freshwater-induced regional oceanic reorganizations we analyzed several sediment sequences from the poorly investigated area along the eastern Greenland margin and the western Nordic Seas. Records span the last interglacial (LIG, MIS5e) cycle, including deglacial Termination 2 and the LIG climatic optimum. On a global scale, the latter is believed to have been warmer than present, with a higher sea level, and may, therefore, serve as a promising analogue for future hydrographic changes. Based on various proxy data (stable isotopes, planktic foraminiferal assemblages, ice-rafted debris) our reconstructions support the notion of a "two-step development" of Termination 2 which underwent severe surface freshening in the subpolar North Atlantic. This is shown in extremely light oxygen isotopic values registered all along the eastern Greenland margin during early MIS5e, which are indicative for pronounced eastern/central GIS retreat and a further propagation of the resulting meltwater southward via the EGC. In addition, we find compelling evidence for at least two separate meltwater episodes in proximity of the eastern GIS during early MIS5e. The climatic episode in between is correlated with an early LIG warm peak, which may be linked to enhanced presence of Atlantic water in the central Nordic Seas (Bauch et al., 2012) and further downstream along southern Greenland (Hillaire-Marcel et al., 1994, Irvali et al., 2012). Our data, therefore, reveal a complex and variable dynamic of the EGC during MIS5e

  17. Liquid freshwater transport estimates from the East Greenland Current based on continuous measurements north of Denmark Strait

    NARCIS (Netherlands)

    de Steur, L.; Pickart, R.S.; Macrander, A.; Våge, K.; Harden, B.; Jónsson, S.; Østerhus, S.; Valdimarsson, H.

    2017-01-01

    Liquid freshwater transports of the shelfbreak East Greenland Current (EGC) and the separated EGC are determined from mooring records from the Kögur section north of Denmark Strait between August 2011 and July 2012. The 11 month mean freshwater transport (FWT), relative to a salinity of 34.8, was 65

  18. A preliminary report on coprolites from the Late Triassic part of the Kap Stewart Formation, Jameson Land, East Greenland

    DEFF Research Database (Denmark)

    Milàn, Jesper; Clemmensen, Lars B; Adolphsen, Jan Schulz;

    2012-01-01

    The basal part of the Triassic-Jurassic (Rhaetian-Sinemurian) Kap Stewart Formation, exposed at Jameson Land, East Greenland, yields an extensive coprolite collection from black, parallel-laminated mudstone (“paper shale”), representing an open lacustrine system. Preliminary investigations show...

  19. Crustal Decoupling in Collisional Orogenesis: Examples from the East Greenland Caledonides and Himalaya

    Science.gov (United States)

    Hodges, K. V.

    2016-06-01

    Mature orogenic systems built by continent-continent collision feature orogenic plateaus flanked by accretionary wedges. Thermal-mechanical models of these systems predict the development of a thermally weakened orogenic infrastructure that is capable of lateral flow toward the orogenic foreland. Such flow, if it occurs, strongly influences the evolutionary pathway of a wedge. Although the architecture of a wedge features numerous large-displacement faults, three are preeminent in mature orogens: one that marks the base of the wedge and two others that mark the base and top, respectively, of the weakened infrastructure. These structures represent major decoupling horizons separating domains with distinctive deformational and thermal histories. Reviews of the geology of orogenic wedges in two mature orogenic systems—the Cenozoic Himalaya and the Paleozoic East Greenland Caledonides—show how this simple conceptual model provides a valuable context for studies of how collisional orogenic systems develop and how they interact with the surrounding lithosphere.

  20. Iceberg Calving and Flow Dynamics at Helheim Glacier, East Greenland, from Time-Lapse Photography

    Science.gov (United States)

    Hamilton, G. S.; Khan, S. A.; Schild, K. M.; Stearns, L. A.; Nettles, M.; Ahlstrøm, A. P.; Andersen, M. L.; Davis, J. L.; Ekström, G.; Elósegui, P.; Forsberg, R.; de Juan, J.; Larsen, T. B.; Stenseng, L.

    2008-12-01

    Helheim Glacier in East Greenland is the focus of coordinated studies aimed at understanding tidewater outlet-glacier dynamics and kinematics, and their link to glacial earthquakes. As part of this effort, we installed three time-lapse cameras overlooking the calving terminus of the glacier during the Arctic summer of 2008. Images were captured every five minutes during the mostly unattended period of operation. Several interesting aspects of the glacier's behavior are observed in the image sequences, including vertical displacement of the glacier terminus by ocean tides, and very large calving events. These observations, in combination with simultaneous measurements of ice flow, ocean tides (including tsunamis) and seismic activity, contribute to our understanding of the dynamics of Helheim Glacier and the source mechanism of glacial earthquakes.

  1. Comparison of the glacial chronology of Eastern Baffin Island, East Greenland and Camp century accumulation record

    DEFF Research Database (Denmark)

    Andrews, John; Funder, Svend Visby; Hjort, Chritian;

    1974-01-01

    level between 120,000 and 70,000 B.P. may well be related to glacierization of high arctic land masses under conditions of heavy snowfall. The subsequent reduction of accumulation in these high arctic areas then leads to a reduction of ice volume with a dry, cold interstadial correlative in time......Independently derived glacial chronologies from eastern Baffin Island, Canadian Arctic, and from East Greenland show essentially similar glaciologic trends that arc notably different from the response of the southern margins of the Laurentide and FCllnoscandia Ice Sheets. The critical aspe......~ts of both chronologies and the related extcn t of the ice sheets are (1) an early and maximum glacial stade, during the early phase of the last glaciation, reaching its peak abqut 100,000 to 75,000 yr ago; (2) an in terstadial about .70,000 n.p.; (3) an ice advance peaking about 45,000 yr ago; (4...

  2. Dynamic behaviour of ice streams: the North East Greenland Ice Stream

    Science.gov (United States)

    Bons, Paul D.; Jansen, Daniela; Schaufler, Svenja; de Riese, Tamara; Sachau, Till; Weikusat, Ilka

    2017-04-01

    The flow of ice towards the margins of ice sheets is far from homogeneous. Ice streams show much higher flow velocities than their surroundings and may extend, for example the North East Greenland Ice Stream (NEGIS), towards the centre of the sheet. The elevated flow velocity inside an ice stream causes marginal shearing and convergent flow, which in turn leads to folding of ice layers. Such folding was documented in the Petermann Glacier in northern Greenland (Bons et al., 2016). 3-dimensional structural modelling using radargrams shows that folding is more intense adjacent to NEGIS than inside it, despite the strong flow perturbation at NEGIS. Analysis of fold amplitude as a function of stratigraphic level indicates that folding adjacent to NEGIS ceased in the early Holocene, while it is currently active inside NEGIS. The presence of folds adjacent of NEGIS, but also at other sites far in the interior of the Greenland Ice Sheet with no direct connection to the present-day surface velocity field, indicates that ice flow is not only heterogeneous in space (as the present-day flow velocity field shows), but also in time. The observations suggest that ice streams are dynamic, ephemeral structures that emerge and die out, and may possibly shift during their existence, but leave traces within the stratigraphic layering of the ice. The dynamic nature of ice streams such as NEGIS speaks against deterministic models for their accelerated flow rates, such as bedrock topography or thermal perturbations at their base. Instead, we suggest that ice streams can also result from strain localisation induced inside the ice sheet by the complex coupling of rheology, anisotropy, grain-size changes and possibly shear heating. Bons, P.D., Jansen, D., Mundel, F., Bauer, C.C., Binder, T., Eisen, O., Jessell, M.W., Llorens, M.-G, Steinbach, F., Steinhage, D. & Weikusat, I. 2016. Converging flow and anisotropy cause large-scale folding in Greenland's ice sheet. Nature Communications 7

  3. The Jurassic of Denmark and Greenland: Shallow marine syn-rift sedimentation: Middle Jurassic Pelion Formation, Jameson Land, East Greenland

    Directory of Open Access Journals (Sweden)

    Engkilde, Michael

    2003-10-01

    Full Text Available The Middle Jurassic Pelion Formation – Fossilbjerget Formation couplet of Jameson Land, East Greenland, is a well-exposed example of the Middle Jurassic inshore–offshore successions characteristicof the rifted seaways in the Northwest European – North Atlantic region. Early Jurassic deposition took place under relatively quiet tectonic conditions following Late Permian – earliest Triassic and Early Triassic rift phases and the Lower Jurassic stratal package shows an overall layer-cake geometry. A long-term extensional phase was initiated in Middle Jurassic (Late Bajocian time, culminated in the Late Jurassic (Kimmeridgian–Volgian, and petered out in the earliest Cretaceous (Valanginian. The Upper Bajocian – Middle Callovian early-rift succession comprises shallow marine sandstones of the Pelion Formation and correlative offshore siltstones of theFossilbjerget Formation. Deposition was initiated by southwards progradation of shallow marine sands of the Pelion Formation in the Late Bajocian followed by major backstepping in Bathonian–Callovian times and drowning of the sandy depositional system in the Middle–Late Callovian. Six facies associations are recognised in the Pelion–Fossilbjerget couplet, representing estuarine, shoreface, offshore transition zone and offshore environments. The north–southtrendingaxis of the Jameson Land Basin had a low inclination, and deposition was sensitive to even small changes in relative sea level which caused the shorelines to advance or retreat over tens to several hundreds of kilometres. Eight composite sequences, termed P1–P8, are recognised and are subdivided into a total of 28 depositional sequences. The duration of the two orders of sequences was about 1–2 Ma and 360,000 years, respectively. The Upper Bajocian P1–2 sequencesinclude the most basinally positioned shallow marine sandstones, deposited during major sealevel lowstands. The lowstands were terminated by significant marine

  4. The Association Between Fog and Temperature Inversions from Ground and Radiosonde Observations in East Greenland

    Science.gov (United States)

    Gilson, G.; Jiskoot, H.

    2016-12-01

    Many Arctic glaciers terminate along coasts where temperature inversions and sea fog are frequent during summer. Both can influence glacier ablation, but the effects of fog may be complex. To understand fog's physical and radiative properties and its association to temperature inversions it is important to determine accurate Arctic coastal fog climatologies In previous research we determined that fog in East Greenland peaks in the melt season and can be spatially extensive over glacierized terrain. In this study we aim to understand which environmental factors influence fog occurrence in East Greenland; understand the association between fog and temperature inversions; and quantify fog height. We analyzed fog observations and other weather data from coastal synoptic weather stations, and extracted temperature inversions from the Integrated Global Radiosonde Archive radiosonde profiles. Fog height was calculated from radiosonde profiles, based on a method developed for radiation fog which we expanded to include advection and steam fog. Our results show that Arctic coastal fog requires sea ice breakup and a sea breeze with wind speed between 1-4 m/s. Fog is mostly advective, occurring under stable synoptic conditions characterized by deep and strong low-level temperature inversions. Steam fog may occur 5-30% of the time. Fog can occur under near-surface subsidence, with a subsaturated inversion base, or a saturated inversion base. We classified five types of fog based on their vertical sounding characteristics: only at the surface, below an inversion, capped by an inversion, inside a surface-based inversion, or inside a low-level inversion. Fog is commonly 100-400 m thick, often reaching the top of the boundary layer. Fog height is greater at northern stations, where daily fog duration is longer and relative humidity lower. Our results will be included in glacier energy-balance models to account for the influence of fog and temperature inversions on glacier melt.

  5. Coeval dust accumulation minima in Greenland and East Central Europe over 31-23 ka

    Science.gov (United States)

    Újvári, Gábor; Stevens, Thomas; Varga, György; Kovács, János; Molnár, Mihály

    2016-04-01

    As reflected in δ18O values in ice cores, the North Atlantic area experienced a series of abrupt, dramatic climatic fluctuations over the last glacial during which oceanic and atmospheric conditions alternated between full glacial (stadial) and relatively mild (interstadial) conditions [1,2]. Beyond the δ18O profiles, calcium ion concentration data (hereafter [Ca2+]) also exhibit particularly clear stadial/interstadial contrasts [3]. The Ca2+/dust concentration records are considered as a proxy for the amount of terrestrial dust reaching the ice sheet [4] and/or changing dust storm activity in the source areas around the Northern Hemisphere, mainly in East Asia [5,6]. The mode of the dust size distributions is thought to reflect transit times during transport, with larger modes indicating shorter transit times and transport routes, i.e. changed atmospheric circulation patterns [5]. However, based on clay mineralogy and Sr-Nd isotopic compositions of loess sediments Újvári, et al. [7] suggested that Central European dust cannot be excluded as a potential source of Greenland dust. As such, it is vital to analyze dust deposition in the key dust depocentres of Eastern Europe. As a record of Carpathian Basin dust source activity, we therefore studied loess sedimentation and grain size changes in the Dunaszekcsö loess sequence in Southern Hungary. For this record, we developed the highest resolution geochronological dataset for European loess based on 61 AMS 14C dates from molluscs and charcoal fragments. This allowed us to establish a uniquely high precision Bayesian age-depth model, with the mean 95% confidence ranges that vary between 119 and 798 yr. Sedimentation rates (SR) calculated from the age-depth model vary between 0.36-1.7 mm yr-1 and the estimated bulk dust mass accumulation rates (MAR) range from 551 to 2525 g m-2 yr-1. Both the SR and MAR display millennial/sub-millennial scale variations, visible uniquely due to the high precision dating, together

  6. Oxygen and carbon isotope composition of Quaternary bivalve shells as a water mass indicator: Last interglacial and Holocene, East Greenland

    DEFF Research Database (Denmark)

    Israelson, C.; Buchardt, Bjørn; Funder, S.V.

    1994-01-01

    to south along the Ea5t Greenland coast \\\\as also present during the Holaccnc dimatil.: optimum 800n -7{JOO yr B.P. Analyses of b;\\'al\\t: shells from the last interglacial sho\\\\! that Scoresby Sund during that time was weB circulated and that mell\\\\Jter from 1h.... Greenland ice sheet and sea ice meltwater......Oxygen and carhon isotope composition of arctic bivahe shells are used in an attempt to reCO'1struct -.urface water temperature and salinities in Scoresby Sund. East Greenland. The oxygen i:;otope compositions or .1,tw mllicuf£!. Hialclla arctica and Tridmlla hOl'm!is han~ been compared...

  7. Geochemistry and tectonomagmatic setting of the Kharaju gabbroic intrusions (South Azarshahr, East Azerbaijan province

    Directory of Open Access Journals (Sweden)

    Abdolnaser Fazlnia

    2016-12-01

    Full Text Available Kharaju mafic intrusions (south Azarshahr; East Azarbaijan are gabbro in composition. The rocks with Eocene age intruded the northwest part of Urumieh -Dokhtar magmatic belt with a trend of NW-SE. These rocks contain mostly of minerals such as plagioclase, quartz, pyroxene, titanite, apatite and magnetite. The rocks are moderate to high calc-alkaline. The gabbros were produced as a result of the partial melting of mantle wedge with spinel lherzolite and after emplacement into the crustal magma chamber underwent fractional crystallization. Injection of the Kharaju intrusions is in relation to the last stages of Neotethys subduction activity under Central Iran. Negative anomaly in the high ionic strength elements (HFSE like, Nb, Ta, P, Hf and Zr and mild positive anomalies of Eu and Sr with moderate increases in values of K, Sr, Rb, Ba, Pb and U show oblique subduction beneath Central Iran might be willing to make the appropriate space on the edge of central Iran and as a result, partial melting in the mantle wedge occurred due to reduce the pressure as decompression.

  8. Xenoestrogenic and dioxin-like activity in blood of East Greenland polar bears (Ursus maritimus).

    Science.gov (United States)

    Erdmann, Simon E; Dietz, Rune; Sonne, Christian; Bechshøft, Thea Ø; Vorkamp, Katrin; Letcher, Robert J; Long, Manhai; Bonefeld-Jørgensen, Eva C

    2013-07-01

    The aims of the project were to (i) extract the lipophilic persistent organic pollutants (POPs) from the blood of 99 East Greenland polar bears and assess the combined mixture effect on the estrogen receptor (ER) and the aryl hydrocarbon receptor (AhR) mediated transactivity; (ii) To evaluate whether the receptor transactivities were associated with selected POP markers, and (iii) compare the receptor transactivities in polar bears with earlier studies on Greenlandic Inuit. Lipophilic POPs were extracted using a combination of solid-phase extraction (SPE) and high performance liquid chromatography (HPLC). ER mediated transactivity was determined using the ER luciferase reporter MVLN cell assay. The extracts were tested alone (XER) and together with 17β-estradiol (E2) as a physiological mimic (XERcomp). Dioxins and dioxin-like (DL) compounds were extracted by a combination of SPE and the Supelco Dioxin Prep System®. AhR mediated dioxin-like transactivity was determined using the AhR luciferase reporter Hepa 1.12cR cell assay. Agonistic ER transactivity was elicited by 19% of the samples, and a further increased E2 induced ER response was found for 52%, whereas 17% antagonized the E2 induced ER response. Positive correlations were found in subadult bears between XER and several POP biomarkers. XER and XERcomp correlated positively to each other. A total of 91% of the polar bear blood extracts elicited agonistic AhR transactivity. The AhR-TCDD equivalent (AhR-TEQ) median levels were higher among adult bears compared to subadult bears, but not significantly.

  9. Organohalogen concentrations and a gross and histologic assessment of multiple organ systems in East Greenland polar bears (Ursus maritimus)

    DEFF Research Database (Denmark)

    Sonne, C.

    To investigate the relation between biological parameters, not earlier investigated in the polar bear, and organohalogen pollution in East Greenland polar bears, we initiated a sampling of adipose tissue, internal organs and skulls from more than 100 free-ranging polar bears killed by local...... in the adipose tissue and pathological changes in skulls and internal organs. Our results suggested a decrease in adipose tissue concentrations of organohalogens in East Greenland polar bears from 1990 to 1999-2001. Two of the biological effect parameters (FA and enlarged clitoris) did not indicate a link......, infectious agents, season and meaby chronic exposure to organohalogens. These result fill out an existing knowledge gap in potential effects of environmental, organic contaminants on fluctuating asymmetry, bone mineral density and functional anatomy (histology) in the polar bear. In addition, the results may...

  10. Multi-decadal record of ice dynamics on Daugaard Jensen Gletscher, East Greenland, from satellite imagery and terrestrial measurements

    DEFF Research Database (Denmark)

    Stearns, L.A.; Hamilton, G.S.; Reeh, Niels

    2005-01-01

    The history of ice velocity and calving front position of Daugaard Jensen Gletscher, a large outlet glacier in East Greenland, is reconstructed from field measurements, aerial photography and satellite imagery for the period 1950-2001. The calving terminus of the glacier has remained in approxima......The history of ice velocity and calving front position of Daugaard Jensen Gletscher, a large outlet glacier in East Greenland, is reconstructed from field measurements, aerial photography and satellite imagery for the period 1950-2001. The calving terminus of the glacier has remained...... vs snow accumulation in the interior catchment show that Daugaard Jensen Gletscher has a small negative mass balance. This result is consistent with other mass-balance estimates for the inland region of the glacier....

  11. The crust and upper mantle of central East Greenland - implications for continental accretion and rift evolution

    Science.gov (United States)

    Schiffer, Christian; Balling, Niels; Ebbing, Jörg; Holm Jacobsen, Bo; Bom Nielsen, Søren

    2016-04-01

    The geological evolution of the North Atlantic Realm during the past 450 Myr, which has shaped the present-day topographic, crustal and upper mantle features, was dominated by the Caledonian orogeny and the formation of the North Atlantic and associated igneous activity. The distinct high altitude-low relief landscapes that accompany the North Atlantic rifted passive margins are the focus of a discussion of whether they are remnant and modified Caledonian features or, alternatively, recently uplifted peneplains. Teleseismic receiver function analysis of 11 broadband seismometers in the Central Fjord Region in East Greenland indicates the presence of a fossil subduction complex, including a slab of eclogitised mafic crust and an overlying wedge of hydrated mantle peridotite. This model is generally consistent with gravity and topography. It is shown that the entire structure including crustal thickness variations and sub-Moho heterogeneity gives a superior gravity and isostatic topographic fit compared to a model with a homogeneous lithospheric layer (1). The high topography of >1000 m in the western part of the area is supported by the c. 40 km thick crust. The eastern part requires buoyancy from the low velocity/low density mantle wedge. The geometry, velocities and densities are consistent with structures associated with a fossil subduction zone. The spatial relations with Caledonian structures suggest a Caledonian origin. The results indicate that topography is isostatically compensated by density variations within the lithosphere and that significant present-day dynamic topography seems not to be required. Further, this structure is suggested to be geophysically very similar to the Flannan reflector imaged north of Scotland, and that these are the remnants of the same fossil subduction zone, broken apart and separated during the formation of the North Atlantic in the early Cenozoic (2). 1) Schiffer, C., Jacobsen, B.H., Balling, N., Ebbing, J. and Nielsen, S

  12. Evolution of a trough-fan system: Scoresby Sund fjord, central-east Greenland

    Science.gov (United States)

    Pérez, Lara F.; Nielsen, Tove; Knutz, Paul C.; Kuijpers, Antoon; Damm, Volkmar

    2016-04-01

    The continental shelf along the east margin of Greenland is shaped by several, glacially carved transverse troughs that constitute the oceanward extension of the major fjords. Scoresby Sund is the most prominent fjord of central-east Greenland and separates Liverpool Land, to the north, from Blosseville Kyst to the south. Offshore of Scoresby Sund a large glacial trough mouth fan (TMF) has been built through successive phases of glacial advances. Morpho-structural and seismo-stratigraphic analyses of the Scoresby Sund TMF have been done using all Multichannel Seismic (MCS) profiles available in the area. The ODP site 987 of the leg 162 is located in the abyssal plain offshore of Scoresby Sund and was used for age estimations. The width of the continental shelf in the study area ranges from a 65 km narrow part along the Blosseville Kyst to 120 km off Scoresby Sund. The average water depth is shallower than 300 m, deepening to 600 m along Scoresby Sund glacial trough. Oceanwards a steep slope, seafloor falls into the 2250 m deep abyssal plain of the south Greenland Sea. The sedimentary cover displays maximum thickness along the middle continental shelf (2.8 s TWTT on average). Seven major stratigraphic discontinuities could be identified within the sedimentary record. They restrict eight major seismic units, named from 8 to 1, in upward stratigraphic order. The distribution and seismic facies of these units reveal the evolutionary sequence of the study area from early Cenozoic to Present. The lowest unit, Unit 8, is post-basalt to middle-late Miocene age and represents a pre-glacial depositional stage when tectonic events controlled the sedimentation. Deposition of Unit 7 occurred by late Miocene, revealing glacial-related deposits and ice-stream along Scoresby Sund fjord. Unit 6 was formed during early Pliocene by glacial advance over the continental shelf leading to strong erosive surfaces in the shelf area and Mass Transport Deposits (MTDs) in the northern abyssal

  13. The Jurassic of East Greenland: a sedimentary record of thermal subsidence, onset and culmination of rifting

    Energy Technology Data Exchange (ETDEWEB)

    Surlyk, F. [Univ. of Copenhagen, Copenhagen (Denmark)]. Geological Inst.

    2003-07-01

    The Late Palaeozoic - Mesozoic extensional basin complex of East Greenland contains a record of deposition during a period of Rhaetian - Early Bajocian thermal subsidence, the onset of rifting in the Late Bajocian, its growth during the Bathonian-Kimmeridgian, culmination of rifting in the Volgian - Early Ryazanian, and waning in the Late Ryazanian - Hauterivian.,The area was centred over a palaeolatitude of about 45 deg C N in the Rhaetian and drifted northwards to about 50 deg C N in the Hauterivian. A major climate change from arid to humid subtropical conditions took place at the Norian-Rhaetian transition. Deposition was in addition governed by a long-term sea-level rise with highstands in the Toarcian-Aalenian, latest Callovian and Kimmeridgian, and lowstands in the latest Bajocian - earliest Bathonian, Middle Oxfordian and Volgian. The Rhaetian - Lower Bajocian succession is considered the upper part of a megasequence, termed Jl, with its base in the upper Lower Triassic, whereas the Upper Bajocian - Hauterivian succession forms a complete, syn-rift megasequence, termed J2. The southem part of the basin complex in Jameson Land contains a relatively complete Rhaetian-Ryazanian succession and underwent only minor tilting during Middle Jurassic - earliest Cretaceous rifting. Rhaetian - Lower Jurassic deposits are absent north of Jameson Land and this region was fragmented into strongly tilted fault blocks during the protracted rift event. The syn-rift successions of the two areas accordingly show different long-term trends in sedimentary facies. In the southern area, the J2 syn-rift megasequence forms a symmetrical regressive-transgressive-regressive cycle, whereas the J2 megasequence in the northem area shows an asymmetrical, stepwise deepening trend. A total of eight tectonostratigraphic sequences are recognised in the Rhaetian-Hauterivian interval. They reflect major changes in basin configuration, drainage systems, sediment transport and distribution

  14. Extended correlation of the Paleogene Faroe Islands and East Greenland plateau basalts

    DEFF Research Database (Denmark)

    Søager, Nina; Holm, Paul Martin

    2008-01-01

    New analytical data are presented for 13 enriched high-Ti tholeiitic basalts from the top of the Faroese lava pile that was formed by the time of break-up of the North Atlantic  56-55  Ma ago and are located on the eastern continental margin of the Atlantic Ocean. The samples fall in three groups....../204Pb = 17.59-18.30 while the High-Ti3 group has 206Pb/204Pb = 18.88-19.12. The three Faroese lava groups can be correlated with the East Greenland syn-breakup basalt formations using their geochemistry, lava morphology and phenocryst contents. The High-Ti1 group correlates with the Milne Land......-Ti1 and Milne Land Formation lavas have a higher content of most incompatible elements compared to High-Ti2 and Geikie Plateau Formation. This is unexpected because the Zr/Nb ratio indicates that the High-Ti2 and Geikie Plateau Formation lavas are formed by lower degrees of melting. An explanation may...

  15. Hydrothermal flake graphite mineralisation in Paleoproterozoic rocks of south-east Greenland

    DEFF Research Database (Denmark)

    Rosing-Schow, Nanna; Bagas, Leon; Kolb, Jochen

    2017-01-01

    Flake graphite mineralisation is hosted in the Kuummiut Terrane of the Paleoproterozoic Nagssugtoqidian Orogen, south-east Greenland. Eclogite-facies peak-metamorphic assemblages record temperatures of 640–830 °C and pressures of 22–25 kbar, and are retrogressed in the high-pressure amphibolite......-facies during ca. 1870–1820 Ma. Graphite occurs as lenses along cleavage planes in breccia and as garnet-quartzgraphite veins in various metamorphic host rocks in the Tasiilaq area at Auppaluttoq, Kangikajik, and Nuuk-Ilinnera. Graphite contents reach >30 vol% in 0.2–4 × 20mwide semimassive mineralisation...... (Auppaluttoq, Kangikajik). Supergene alteration formed 1- to 2-m-thick and up to a 2.5 × 2.5 km wide loose limonitic gravel containing graphite flakes in places. The flake size ranges from 1 to6mm in diameter with an average of ~3 mm. Liberation efficiency is at minimum 60%. Hydrothermal fluids at ~600 °C...

  16. Geometry and kinematics of the Triassic rift basin in Jameson Land (East Greenland)

    Science.gov (United States)

    Guarnieri, Pierpaolo; Brethes, Anaïs.; Rasmussen, Thorkild M.

    2017-04-01

    The Triassic rift basin along the east Greenland margin described in this paper is represented by NE-SW trending basins and highs segmented by NW-SE trending transfer zones. Coarse-grained sediments along the eastern side of Jameson Land are shown to be hosted in half-graben structures belonging to the Carlsberg Fjord Basin that is bounded by NW dipping normal faults mapped and described after fieldwork in the Klitdal area in Liverpool Land. New aeromagnetic and electromagnetic data together with new drill cores allow the reinterpretation of available seismic lines showing the continuation of the Triassic rift basin toward the SW where it is buried under the Upper Triassic postrift sediments and the Jurassic successions of the Jameson Land Basin. The N-S trending Liverpool Land, interpreted as the boundary block of the Triassic basin, is shown to represent a structural high inherited from the Late Carboniferous tectonics and faulted during the Triassic rifting. The Carlsberg Fjord Basin and the Klitdal Fault System described in this paper should be seen as analogues to the Helgeland Basin in the Norwegian offshore that is bounded by the Ylvingen Fault Zone and to the Papa and West of Shetlands Basins that are bounded by the Spine Fault. The Triassic rift zone and transfer faults on both conjugate margins show a straightforward correlation with the trends of the initial spreading line and fracture zones of the northeast Atlantic indicating a possible inheritance of the Triassic rifting.

  17. Terra nullius, Inuit Habitation and Norse Occupation – With Special Emphasis on the 1933 East Greenland Case

    Directory of Open Access Journals (Sweden)

    Peter Thomas Ørebech

    2016-05-01

    Full Text Available Sovereignty acquired by occupation entails “recognize[d] title based on discovery,” “a reasonable period [of] … effective occupation of the region claimed to be discovered” and “the continuous and peaceful display of State authority.” Only terra nullius is subject to occupation. A territory inhabited by indigenous groups that sustain social and political organization may impede an occupying power because the terra nullius requirement fails. While sovereignty over thinly populated areas are often lax, case law requires less public involvement in these sparsely inhabited areas. This study reveals that the Dano-Norwegian Kings regarded the Inuit as “our subjects.” The Kings’ pretention of absolutum dominium and jurisdiction involved both the Norse and Inuit ethnic groups and “bygð ok ubygð” (settled and unsettled land. The exodus of the Norse peoples in 1450 AD for 200 years did not undermine the acquired sovereignty of the Dano-Norwegian Crown, which as a result, spoiled the 1931 Norwegian pretentions to legally occupy East-Greenland. Denmark's triumph in the 1933-East Greenland case resulted from a “zero-sum principle.” More than a 100 years earlier, the Danish Kingdom lost a succession of countries and dependencies. The 1814 Kiel Treaty transferred mainland Norway to Sweden, but explicitly states that none of the ancient Norwegian dependencies, Greenland, Iceland and Faroe Islands would follow suit. Thus, these territories remained part of the Kingdom of Denmark.

  18. THE INTRUSION AND INFLUENCES OF INTRASEASONAL LONG ROSSBY WAVES IN THE EAST CHINA SEA

    Institute of Scientific and Technical Information of China (English)

    LIN Xiao-pei; WU De-xing; LAN Jian

    2004-01-01

    The analysis of sea level data from tide stations and ocean general circulation model(OGCM)shows that the intraseasonal long Rossby wave results in the intraseasonal variations of Kuroshio axis and transport in the upper reaches of the Kuroshio in the East China Sea(ECS).Due to the transport modulation induced by Ryukyu Islands,the intraseasonal variation is very weak in the lower reaches of the Kuroshio in the ECS.A two-layer model reveals the relation among Kuroshio frontal unstable wave with topography,transport and the axis position of the Kuroshio,from which we can infer that the intrusion of intraseasonal long Rossby wave may stimulate the Kuroshio frontal unstable wave in the upper reaches of the Kuroshio in the ECS.The altimeter data also shows that the sea level anomaly resulting from intraseasonal long Rossby wave could pass the channel between Taiwan and Ryukyu Islands and propagate northeastward in accord with the Kuroshio frontal unstable wave.However,the sea level anomalies passing through the gaps of Ryukyu Islands are relative weak and have negligible effects on the Kuroshio variation.

  19. Immiscible iron- and silica-rich melt in basalt petrogenesis documented in the Skaergaard intrusion

    DEFF Research Database (Denmark)

    Jakobsen, Jakob Kløve; Veksler, Ilya; Tegner, Christian;

    2005-01-01

    yet to be proven. Here we report the first finding of natural, immiscible iron- and silica-rich melts in a plutonic environment documented in the Skaergaard intrusion, East Greenland. Primary melt inclusions (now finely crystallized) in apatite are either dark or light colored. The predominant dark...

  20. Late Pleistocene to early Holocene environmental changes on Store Koldewey, coastal north-east Greenland

    Directory of Open Access Journals (Sweden)

    Martin Klug

    2016-12-01

    Full Text Available A lake sediment sequence from southern Store Koldewey, north-east Greenland, has been investigated using a multidisciplinary approach, including geophysical, geochemical, biogeochemical, biological and sedimentological methods. Chronological constraints are provided by accelerator mass spectrometry (AMS 14C dating of bulk sediment and complemented with published water moss ages. The record consists of three major sediment units. Their individual structural, textural, geophysical and geochemical characteristics indicate variable input of sediment and meltwater due to variable proximity of the ice margin and therefore reflect the growth and decay of a local glacier during the late Weichselian. Radiocarbon dating of bulk sediment samples from the lowermost unit gave ages of 42 to 34 calibrated thousand years (cal Ky B.P. and indicates that this material is redeposited in the lake basin during or after the ice advance at the end of the Pleistocene. Increased meltwater and sediment input from a retreating ice margin following the Younger Dryas is indicated by the occurrence of a sandy to gravely section. Fine-grained and laminated sediments were deposited during the Pleistocene–Holocene transition and indicate calm sedimentation conditions with an ice margin outside of the lake catchment. The reoccurrence of coarse sediments during the early Holocene may indicate increased meltwater input in response to the cold spell at about 9.3 Kya with increased snow accumulation rather than fluctuations of local glaciers. The dating results furthermore show that AMS 14C dating of bulk sediment samples deposited during glacier decay in High Arctic environments can give problematic ages.

  1. Depositional environment and organic geochemistry of the Upper Permian Ravenfjeld Formation source rock in East Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Christiansen, F.G.; Piasecki, S.; Stemmerik, L. (Geologoical Survey of Greenland, Copenhagen (Denmark)); Telnaes, N. (Norsk Hydro Research Center, Bergen (Norway))

    1993-09-01

    The Upper Permian Ravnefjeld Formation in East Greenland is composed of shales that laterally pass into carbonate buildups and platforms of the Wegener Halvo Formation. The Ravnefjeld Formation is subdivided into five units that can be traced throughout the Upper Permian depositional basin. Two of the units are laminated and organic rich and were deposited under anoxic conditions. They are considered good to excellent source rocks for liquid hydrocarbons with initial average TOC (total organic carbon) values between 4 and 5% and HI (hydrogen index) between 300 and 400. The cumulative source rocks are separated and enclosed by three units of bioturbated siltstone with a TOC of less than 0.5% and an HI of less than 100. These siltstones were deposited under relatively oxic conditions. The organic geochemistry of the source rocks is typical for marine source rocks with some features normally associated with carbonate/evaporite environments [low Pr/Ph (pristane/phytane), low CPI (carbon preference index), distribution of tricyclic and pentacyclic terpanes]. The establishment of anoxic conditions and subsequent source rock deposition was controlled by eustatic sea level changes. The subenvironment (paleogeographic setting, influx of carbonate material, water depth, salinity) has some influence on a number of bulk parameters [TOC-HI relations, TOC-TS (total sulfur) relations] and, in particular, biomarker parameters such as Pr/Ph and terpane ratios. All the basal shales or shales in the vicinity of carbonate buildups of platforms are characterized by low Pr/Ph, high C[sub 23] tricyclic terpanes, and high C[sub 35] and C[sub 33] hopanes. 52 refs., 20 figs., 3 tabs.

  2. Hydrothermal flake graphite mineralisation in Paleoproterozoic rocks of south-east Greenland

    Science.gov (United States)

    Rosing-Schow, Nanna; Bagas, Leon; Kolb, Jochen; Balić-Žunić, Tonči; Korte, Christoph; Fiorentini, Marco L.

    2017-06-01

    Flake graphite mineralisation is hosted in the Kuummiut Terrane of the Paleoproterozoic Nagssugtoqidian Orogen, south-east Greenland. Eclogite-facies peak-metamorphic assemblages record temperatures of 640-830 °C and pressures of 22-25 kbar, and are retrogressed in the high-pressure amphibolite-facies during ca. 1870-1820 Ma. Graphite occurs as lenses along cleavage planes in breccia and as garnet-quartz-graphite veins in various metamorphic host rocks in the Tasiilaq area at Auppaluttoq, Kangikajik, and Nuuk-Ilinnera. Graphite contents reach >30 vol% in 0.2-4 × 20 m wide semi-massive mineralisation (Auppaluttoq, Kangikajik). Supergene alteration formed 1- to 2-m-thick and up to a 2.5 × 2.5 km wide loose limonitic gravel containing graphite flakes in places. The flake size ranges from 1 to 6 mm in diameter with an average of 3 mm. Liberation efficiency is at minimum 60%. Hydrothermal fluids at 600 °C, transporting carbon as CO2 and CH4, formed the mineralisation commonly hosted by shear zones, which acted as pathways for the mineralising fluids. The hydrothermal alteration assemblage is quartz-biotite-grunerite-edenite-pargasite-K-feldspar-titanite. The δ13C values of graphite, varying from -30 to -18‰ PDB, indicate that the carbon was derived from organic matter most likely from metasedimentary sources. Devolatilisation of marble may have contributed a minor amount of carbon by fluid mixing. Precipitation of graphite involved retrograde hydration reactions, depleting the fluid in H2O and causing graphite saturation. Although the high-grade mineralisation is small, it represents an excellent example of hydrothermal mineralisation in an eclogite-facies terrane during retrograde exhumation.

  3. Micromorphology of diamicton affected by iceberg-keel scouring, Scoresby Sund, East Greenland

    Science.gov (United States)

    Linch, Lorna D.; Dowdeswell, Julian A.

    2016-11-01

    Icebergs are important as agents of deposition and seafloor reworking on glacier-influenced continental margins. When the keel of an iceberg exceeds water depth it ploughs through soft sediments producing scours/ploughmarks that can be kilometres long, hundreds of metres wide and sometimes tens of metres deep. Because the influence of iceberg keels on sediment is a critical factor when offshore structures (e.g. pipelines, power cables) are installed, the surface morphology of iceberg scours on the seafloor is relatively well-documented. Less however, is known about sub-scour deformation below the seafloor. This is particularly true of iceberg scoured diamicton (poorly sorted sediment comprising a variety of particle sizes), which is present in many high-latitude fjords and continental shelves. The aim of this research is to examine directly (macroscopically and microscopically, with thin sections) the style and intensity of deformation caused by the scouring action of iceberg keels in diamicton offshore of East Greenland. Results show that a distinctive suite of deformation structures (individual structures and overprinted structural patterns) dominated by planar shear, sediment mixing and high porewater, and dropstones characterises iceberg scoured diamicton. In addition, diamicton from areas of high-intensity iceberg scouring tends to show a wider variety, higher frequency and distribution, more abundant and better-developed deformation structures than diamicton from areas of intermediate- and low-intensity iceberg scouring. Characterising the effects of iceberg scour in diamicton is important more widely to inform: i) reconstruction of the geometry and dynamics of former ice sheets; and ii) installation and protection of offshore engineering structures in diamicton where iceberg scouring presents a geohazard. The value of micromorphology is significant especially in the absence of macroscopic sediment exposures/outcrops where the study of cores is necessary

  4. Hydrothermal flake graphite mineralisation in Paleoproterozoic rocks of south-east Greenland

    Science.gov (United States)

    Rosing-Schow, Nanna; Bagas, Leon; Kolb, Jochen; Balić-Žunić, Tonči; Korte, Christoph; Fiorentini, Marco L.

    2016-11-01

    Flake graphite mineralisation is hosted in the Kuummiut Terrane of the Paleoproterozoic Nagssugtoqidian Orogen, south-east Greenland. Eclogite-facies peak-metamorphic assemblages record temperatures of 640-830 °C and pressures of 22-25 kbar, and are retrogressed in the high-pressure amphibolite-facies during ca. 1870-1820 Ma. Graphite occurs as lenses along cleavage planes in breccia and as garnet-quartz-graphite veins in various metamorphic host rocks in the Tasiilaq area at Auppaluttoq, Kangikajik, and Nuuk-Ilinnera. Graphite contents reach >30 vol% in 0.2-4 × 20 m wide semi-massive mineralisation (Auppaluttoq, Kangikajik). Supergene alteration formed 1- to 2-m-thick and up to a 2.5 × 2.5 km wide loose limonitic gravel containing graphite flakes in places. The flake size ranges from 1 to 6 mm in diameter with an average of 3 mm. Liberation efficiency is at minimum 60%. Hydrothermal fluids at 600 °C, transporting carbon as CO2 and CH4, formed the mineralisation commonly hosted by shear zones, which acted as pathways for the mineralising fluids. The hydrothermal alteration assemblage is quartz-biotite-grunerite-edenite-pargasite-K-feldspar-titanite. The δ13C values of graphite, varying from -30 to -18‰ PDB, indicate that the carbon was derived from organic matter most likely from metasedimentary sources. Devolatilisation of marble may have contributed a minor amount of carbon by fluid mixing. Precipitation of graphite involved retrograde hydration reactions, depleting the fluid in H2O and causing graphite saturation. Although the high-grade mineralisation is small, it represents an excellent example of hydrothermal mineralisation in an eclogite-facies terrane during retrograde exhumation.

  5. Middle to late Holocene fluctuations of the Vindue glacier, an outlet glacier of the Greenland Ice Sheet, central East Greenland.

    Science.gov (United States)

    Levy, L.; Hammer, S. K.; Kelly, M. A.; Lowell, T. V.; Hall, B. L.; Howley, J. A.; Wilcox, P.; Medford, A.

    2014-12-01

    The margins of the Greenland Ice Sheet are currently responding to present-day climate changes. Determining how the ice sheet margins have responded to past climate changes provides a means to understand how they may respond in the future. Here we present a multi-proxy record used to reconstruct the Holocene fluctuations of the Vindue glacier, an ice sheet outlet glacier in eastern Greenland. Lake sediment cores from Qiviut lake (informal name), located ~0.75 km from the present-day Vindue glacier margin contain a sharp transition from medium sand/coarse silt to laminated gyttja just prior to 6,340±130 cal yr BP. We interpret this transition to indicate a time when the Vindue glacier retreated sufficiently to cease glacial sedimentation into the lake basin. Above this contact the core contains laminated gyttja with prominent, ~0.5 cm thick, silt layers. 10Be ages of boulders on bedrock located between Qiviut lake and the present-day ice margin date to 6.81 ± 0.67 ka (n = 3), indicating the time of deglaciation. These ages also agree well with the radiocarbon age of the silt-gyttja transition in Qiviut lake cores. 10Be ages on boulders on bedrock located more proximal to the ice margin (~0.5 km) yield ages of 2.67 ± 0.18 ka (n = 2). These ages indicate either the continued recession of the ice margin during the late Holocene or an advance at this time. Boulders on the historical moraines show that ice retreated from the moraine by AD 1620 ± 20 yrs (n = 2). These results are in contrast with some areas of the western margin of the ice sheet where 10Be ages indicate that the ice sheet was behind its Historical limit from the middle Holocene (~6-7 ka) to Historical time. This may indicate that the eastern margin may have responded to late Holocene cooling more sensitively or that the advance associated with the Historical moraines overran any evidence of late Holocene fluctuations along the western margin of the ice sheet.

  6. Source apportionment of particles at Station Nord, North East Greenland during 2008–2010 using COPREM and PMF analysis

    DEFF Research Database (Denmark)

    Nguyen, Quynh; Skov, Henrik; Sørensen, Lise Lotte;

    2013-01-01

    , which were all influenced by metal industries. One anthropogenic source was dominated by Zn of which air mass back trajectories using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model suggested a Canadian Arctic origin, despite certain influences from Southern and Eastern......In order to develop strategies for controlling and reducing Arctic air pollution, there is a need to understand the basic mechanisms for determining the fate of air pollution in the Arctic. Sources of atmospheric particles at Station Nord (81° 36' N, 16° 40' W) in North East Greenland were...

  7. Field metabolic rate and PCB adipose tissue deposition efficiency in East Greenland polar bears derived from contaminant monitoring data.

    Science.gov (United States)

    Pavlova, Viola; Nabe-Nielsen, Jacob; Dietz, Rune; Svenning, Jens-Christian; Vorkamp, Katrin; Rigét, Frank Farsø; Sonne, Christian; Letcher, Robert J; Grimm, Volker

    2014-01-01

    Climate change will increasingly affect the natural habitat and diet of polar bears (Ursus maritimus). Understanding the energetic needs of polar bears is therefore important. We developed a theoretical method for estimating polar bear food consumption based on using the highly recalcitrant polychlorinated biphenyl (PCB) congener, 2,2',4,4',55-hexaCB (CB153) in bear adipose tissue as an indicator of food intake. By comparing the CB153 tissue concentrations in wild polar bears with estimates from a purposely designed individual-based model, we identified the possible combinations of field metabolic rates (FMR) and CB153 deposition efficiencies in East Greenland polar bears. Our simulations indicate that if 30% of the CB153 consumed by polar bear individuals were deposited into their adipose tissue, the corresponding FMR would be only two times the basal metabolic rate. In contrast, if the modelled CB153 deposition efficiency were 10%, adult polar bears would require six times more energy than that needed to cover basal metabolism. This is considerably higher than what has been assumed for polar bears in previous studies though it is similar to FMRs found in other marine mammals. An implication of this result is that even relatively small reductions in future feeding opportunities could impact the survival of East Greenland polar bears.

  8. Field metabolic rate and PCB adipose tissue deposition efficiency in East Greenland polar bears derived from contaminant monitoring data.

    Directory of Open Access Journals (Sweden)

    Viola Pavlova

    Full Text Available Climate change will increasingly affect the natural habitat and diet of polar bears (Ursus maritimus. Understanding the energetic needs of polar bears is therefore important. We developed a theoretical method for estimating polar bear food consumption based on using the highly recalcitrant polychlorinated biphenyl (PCB congener, 2,2',4,4',55-hexaCB (CB153 in bear adipose tissue as an indicator of food intake. By comparing the CB153 tissue concentrations in wild polar bears with estimates from a purposely designed individual-based model, we identified the possible combinations of field metabolic rates (FMR and CB153 deposition efficiencies in East Greenland polar bears. Our simulations indicate that if 30% of the CB153 consumed by polar bear individuals were deposited into their adipose tissue, the corresponding FMR would be only two times the basal metabolic rate. In contrast, if the modelled CB153 deposition efficiency were 10%, adult polar bears would require six times more energy than that needed to cover basal metabolism. This is considerably higher than what has been assumed for polar bears in previous studies though it is similar to FMRs found in other marine mammals. An implication of this result is that even relatively small reductions in future feeding opportunities could impact the survival of East Greenland polar bears.

  9. Are liver and renal lesions in East Greenland polar bears (Ursus maritimus associated with high mercury levels?

    Directory of Open Access Journals (Sweden)

    Born Erik W

    2007-04-01

    Full Text Available Abstract Background In the Arctic, polar bears (Ursus maritimus bio-accumulate mercury as they prey on polluted ringed seals (Phoca hispida and bearded seals (Erignathus barbatus. Studies have shown that polar bears from East Greenland are among the most mercury polluted species in the Arctic. It is unknown whether these levels are toxic to liver and kidney tissue. Methods We investigated the histopathological impact from anthropogenic long-range transported mercury on East Greenland polar bear liver (n = 59 and kidney (n = 57 tissues. Results Liver mercury levels ranged from 1.1–35.6 μg/g wet weight and renal levels ranged from 1–50 μg/g wet weight, of which 2 liver values and 9 kidney values were above known toxic threshold level of 30 μg/g wet weight in terrestrial mammals. Evaluated from age-correcting ANCOVA analyses, liver mercury levels were significantly higher in individuals with visible Ito cells (p Conclusion Based on these relationships and the nature of the chronic inflammation we conclude that the lesions were likely a result of recurrent infections and ageing but that long-term exposure to mercury could not be excluded as a co-factor. The information is important as it is likely that tropospheric mercury depletion events will continue to increase the concentrations of this toxic heavy metal in the Sub Arctic and Arctic marine food webs.

  10. Palynofloral associations before and after the Permian-Triassic mass extinction, Kap Stosch, East Greenland

    Science.gov (United States)

    Schneebeli-Hermann, Elke; Hochuli, Peter A.; Bucher, Hugo

    2017-08-01

    The Permian-Triassic boundary (PTB) interval is known to document a major biodiversity crisis in the history of life. It is generally accepted that this crisis had a significant impact on marine invertebrates. The consequences for terrestrial ecosystems are still controversially discussed. Based on palynological analysis we present a high time resolution microfloral succession of the expanded Late Permian (Wuchiapingian)-Early Triassic (Dienerian) section from Kap Stosch, East Greenland. The quantitative distribution of palynomorphs (range charts and relative abundance data) allows for the differentiation of six distinct palynofloral associations. Ammonoids and conodonts provide independent age control for these assemblages. The Wuchiapingian association I, documented from the Ravnefjeld Formation, shows a typical Late Permian assemblage dominated by bisaccate and monosaccate pollen grains and Vittatina spp. It is separated from association II, present in the basal part of the Wordie Creek Formation, by an important hiatus. This association of Changhsingian or earliest Griesbachian age is characterised by the common occurrence of Ephedripites spp. and reduced abundance and diversity of Vittatina spp. Association III, dated as Griesbachian by the presence of ammonoids, is marked by high relative abundances of taeniate bisaccate pollen grains and high spore diversity. A distinct floral break occurs between the gymnosperm dominated Permian and Griesbachian floras and the lycopsid spore dominated Dienerian associations IV-VI. Ammonoid occurrences verify a Dienerian age for the latter associations. Association V is marked by the absence of non-taeniate bisaccate, striate monosaccate pollen grains, and Vittatina spp. Aratrisporites spp. a typical Triassic lycopsid spore occur consistently from this level onwards. Association VI is characterised by highest lycopsid spore abundances. Cluster analysis demonstrates that Griesbachian assemblages (associations II?-III) are

  11. Parasites as biological tags to track an ontogenetic shift in the feeding behaviour of Gadus morhua off West and East Greenland.

    Science.gov (United States)

    Münster, Julian; Klimpel, Sven; Fock, Heino O; MacKenzie, Ken; Kuhn, Thomas

    2015-07-01

    Parasites, being an integral part of every ecosystem and trophically transmitted along the food webs, can provide detailed insights into the structure of food webs and can close the information gap between short-term stomach content analyses and long-term fish otolith analyses. They are useful for tracking ontogenetic shifts in the host's diet, the occurrence of specific organisms or migratory behaviour of their hosts, even in inaccessible environments. In the present study, stomach content analyses and parasitological examinations were performed on 70 Atlantic cod Gadus morhua, one of the most important high-level predators of small fish in the North Atlantic, caught during one research vessel cruise from West and East Greenlandic waters. Analyses revealed significant differences in fish size with higher values for East Greenland (average total length (TL) of 50.5 cm) compared to West Greenland (average TL of 33.3 cm). Clear differences were also present in prey and parasite composition. Crustacea was the main food source for all fish (IRI = 10082.70), while the importance of teleosts increased with fish size. With a prevalence of 85 % in West Greenland and 100 % in East Greenland, Nematoda were the most abundant parasite group. The results indicate an ontogenetic shift in the diet, which are discussed in the context of the common distribution theory, stock dynamics and migratory behaviour.

  12. Parental magma of the Skaergaard intrusion: constraints from melt inclusions in primitive troctolite blocks and FG-1 dykes

    DEFF Research Database (Denmark)

    Jakobsen, J.K.; Tegner, Christian; Brooks, Kent;

    2010-01-01

    Abstract Troctolite blocks with compositions akin to the Hidden Zone are exposed in a tholeiitic dyke cutting across the Skaergaard intrusion, East Greenland. Plagioclase in these blocks contains finely crystallised melt inclusions that we have homogenised to constrain the parental magma to 47...

  13. The Jurassic of Denmark and Greenland: The Jurassic of East Greenland: a sedimentary record of thermal subsidence, onset and culmination of rifting

    Directory of Open Access Journals (Sweden)

    Surlyk, Finn

    2003-10-01

    Full Text Available The Late Palaeozoic – Mesozoic extensional basin complex of East Greenland contains a record of deposition during a period of Rhaetian – Early Bajocian thermal subsidence, the onset of riftingin the Late Bajocian, its growth during the Bathonian–Kimmeridgian, culmination of rifting in the Volgian – Early Ryazanian, and waning in the Late Ryazanian – Hauterivian. The area was centred over a palaeolatitude of about 45°N in the Rhaetian and drifted northwards to about 50°N in the Hauterivian. A major climate change from arid to humid subtropical conditions took place at the Norian–Rhaetian transition. Deposition was in addition governed by a long-term sea-level rise with highstands in the Toarcian–Aalenian, latest Callovian and Kimmeridgian, and lowstands in the latest Bajocian – earliest Bathonian, Middle Oxfordian and Volgian.The Rhaetian – Lower Bajocian succession is considered the upper part of a megasequence, termed J1, with its base in the upper Lower Triassic, whereas the Upper Bajocian – Hauterivian succession forms a complete, syn-rift megasequence, termed J2. The southern part of the basin complex in Jameson Land contains a relatively complete Rhaetian–Ryazanian succession and underwent only minor tilting during Middle Jurassic – earliest Cretaceous rifting. Rhaetian – Lower Jurassic deposits are absent north of Jameson Land and this region was fragmented into strongly tilted fault blocks during the protracted rift event. The syn-rift successions of the two areas accordingly show different long-term trends in sedimentary facies. In the southern area, the J2 syn-rift megasequence forms a symmetrical regressive–transgressive–regressive cycle, whereas the J2 megasequence in the northern area shows an asymmetrical, stepwise deepening trend.A total of eight tectonostratigraphic sequences are recognised in the Rhaetian–Hauterivian interval. They reflect major changes in basin configuration, drainage systems

  14. Petrology and geochemistry of intrusive body of iron deposit of Sarab-3, east of Takab-north west of Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Maanijou

    2016-09-01

    Full Text Available The Sarab-3 intrusive bodyis located in the NW of Iran, in Sanandaj-Sirjan zone and in the east of Takab city. Based on field observations as well as petrographic features, the lithologic composition of intrusion (Miocene age ranges within the diorite-leucodiorite, monzodiorite, quartz monzodiorite, granodiorite and granite. In terms of geochemical characteristics, the rocks studied, are I-type, with calc-alkaline affinity and meta-aluminous character. Enrichment of LILE (K, U, Sr, Ce, Th, Pb, Ba and LREE relative to HFSE (Zr, Y, Ti, P, Nb and HREE, low Ce / Pb and Nb / U ratios and high Ba / Nb reveal that the rocks under study were originated in an active continental margin subduction-related tectonic setting. The negative anomalies of Ti, Nb and P on the spider diagram also confirm this fact. Low ratios of (Na2O + K2O / (FeOt + MgO + TiO2 and (Al2O3 / FeOt + MgO + TiO2 along with low Rb/Sr concentration (< 0.6 propose that the Sarab-3 intrusive rock is derived from a meta-basaltic source.

  15. Bryophytes collected during a Dutch botanical East Greenland expedition to the Angmagsslalik area in 1966

    NARCIS (Netherlands)

    Molenaar, de J.G.

    1968-01-01

    From a bryological point of view Greenland is not well known in detail. Unlike Siberia or Arctic America, it is not known through a few large collections, but through multitudes of mostly relatively small gatherings. In this arctic island that is almost 2000 miles long and extends from below 60° N.l

  16. Vegetation phenology gradients along the west and east coasts of Greenland from 2001 to 2015

    DEFF Research Database (Denmark)

    Karami, Mojtaba; Hansen, Birger; Westergaard-Nielsen, Andreas

    2017-01-01

    The objective of this paper is to characterize the spatiotemporal variations of vegetation phenology along latitudinal and altitudinal gradients in Greenland, and to examine local and regional climatic drivers. Time-series from the Moderate Resolution Imaging Spectroradiometer (MODIS) were analyzed...

  17. Late Permian-earliest Triassic high-resolution organic carbon isotope and palynofacies records from Kap Stosch (East Greenland)

    Science.gov (United States)

    Sanson-Barrera, Anna; Hochuli, Peter A.; Bucher, Hugo; Schneebeli-Hermann, Elke; Weissert, Helmut; Adatte, Thierry; Bernasconi, Stefano M.

    2015-10-01

    During and after the end Permian mass extinction terrestrial and marine biota underwent major changes and reorganizations. The latest Permian and earliest Triassic is also characterized by major negative carbon isotope shifts reflecting fundamental changes in the carbon cycle. The present study documents a high-resolution bulk organic carbon isotope record and palynofacies analysis spanning the latest Permian-earliest Triassic of East Greenland. An almost 700 meter thick composite section from Kap Stosch allowed discriminating 6 chemostratigraphic intervals that provide the basis for the correlation with other coeval records across the world, and for the recognition of basin wide transgressive-regressive events documenting tectonic activity during the opening of the Greenland-Norway Basin. The identification of the main factors that influenced the organic carbon isotope signal during the earliest Triassic (Griesbachian to Dienerian) was possible due to the combination of bulk organic carbon isotope, palynofacies and Rock-Eval data. Two negative carbon isotopic shifts in the Kap Stosch record can be correlated with negative shifts recorded in coeval sections across the globe. A first negative shift precedes the base of the Triassic as defined by the first occurrence of the conodont Hindeodus parvus in the Meishan reference section, and the second one coincides with the suggested Griesbachian-Dienerian boundary. This new organic carbon isotope record from the extended Kap Stosch section from the Boreal Realm documents regional and global carbon cycle signals of the interval between the latest Palaeozoic and the onset of the Mesozoic.

  18. Exposure to mixtures of organohalogen contaminants and associative interactions with thyroid hormones in East Greenland polar bears (Ursus maritimus)

    DEFF Research Database (Denmark)

    Villanger, Gro D.; Jenssen, Bjørn M.; Fjeldberg, Rita R.

    2011-01-01

    We investigated the multivariate relationships between adipose tissue residue levels of 48 individual organohalogen contaminants (OHCs) and circulating thyroid hormone (TH) levels in polar bears (Ursus maritimus) from East Greenland (1999–2001, n=62), using projection to latent structure (PLS...... influenced by biological factors such as age, sex, body size, lipid content of adipose tissue and sampling date. When controlling for biological variables, the major relationships from the PLS models for SubA, AdF_N and AdF_S were found significant in partial correlations. The most important OHCs...... that influenced TH levels in the significant PLS models may potentially act through similar mechanisms on the hypothalamic–pituitary–thyroid (HPT) axis, suggesting that both combined effects by dose and response addition and perhaps synergistic potentiation may be a possibility in these polar bears. Statistical...

  19. Source apportionment of particles at Station Nord, North East Greenland during 2008–2010 using COPREM and PMF analysis

    DEFF Research Database (Denmark)

    Nguyen, Quynh; Skov, Henrik; Sørensen, Lise Lotte

    2013-01-01

    In order to develop strategies for controlling and reducing Arctic air pollution, there is a need to understand the basic mechanisms for determining the fate of air pollution in the Arctic. Sources of atmospheric particles at Station Nord (81° 36' N, 16° 40' W) in North East Greenland were......, which were all influenced by metal industries. One anthropogenic source was dominated by Zn of which air mass back trajectories using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model suggested a Canadian Arctic origin, despite certain influences from Southern and Eastern...... evaluated for a two-year period from March 2008 to February 2010. Source apportionment using Positive Matrix Factorization (PMF) and COnstrained Physical REceptor Model (COPREM) was based on measurements of black carbon, elements (Al, Si, S, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, As, Se, Br, Rb, Sr, Zr...

  20. Species of Thaumatomastix (Thaumatomastigidae, Protista incertae sedis) from the Arctic sea ice biota (North-East Water Polynya, NE Greenland)

    Science.gov (United States)

    Thomsen, Helge Abildhauge; Ikävalko, Johanna

    1997-01-01

    The sea ice biota of polar regions contains numerous heterotrophic flagellates very few of which have been properly identified. The whole mount technique for transmission electron microscopy enables the identification of loricate and scaly forms. A survey of Arctic ice samples (North-East Water Polynya, NE Greenland) revealed the presence of ca. 12 taxa belonging to the phagotrophic genus Thaumatomastix (Protista incertae sedis). Species of Thaumatomastix possess siliceous body scales and one naked and one scale-covered flagellum. The presence in both Arctic samples and sea ice material previously examined from the Antarctic indicates that this genus is most likely ubiquitous in polar sea ice and may be an important component in sea ice biota microbial activities.

  1. Pb isotopes during crustal melting and magma mingling - A cautionary tale from the Miki Fjord macrodike, central east Greenland

    DEFF Research Database (Denmark)

    Waight, Tod Earle; Lesher, Charles

    2010-01-01

    Pb isotopic data are presented for hybrid rocks formed by mingling between mantle-derived tholeiitic magma of the Eocene Miki Fjord macrodike (East Greenland) and melt derived from the adjacent Precambrian basement. Bulk mixing and AFC processes between end-members readily identified in the field...... fail to model the Pb isotope systematics. Selective contamination during diffusional exchange, which can explain the complex Sr and Nd isotope compositions of the hybrid rocks (Blichert-Toft et al., 1992), cannot fully account for the variability of the Pb isotopic data using the identified crustal end......-members. The crustal anatectic end-member, although similar in Sr and Nd isotope composition, has a markedly different Pb isotopic composition than its source gneiss. The differences are consistent with preferential incorporation of radiogenic Pb from accessory phases such as metamict zircon or loosely-bound Pb from...

  2. Pb isotopes during crustal melting and magma mingling - A cautionary tale from the Miki Fjord macrodike, central east Greenland

    DEFF Research Database (Denmark)

    Waight, Tod Earle; Lesher, Charles

    2010-01-01

    Pb isotopic data are presented for hybrid rocks formed by mingling between mantle-derived tholeiitic magma of the Eocene Miki Fjord macrodike (East Greenland) and melt derived from the adjacent Precambrian basement. Bulk mixing and AFC processes between end-members readily identified in the field...... fail to model the Pb isotope systematics. Selective contamination during diffusional exchange, which can explain the complex Sr and Nd isotope compositions of the hybrid rocks (Blichert-Toft et al., 1992), cannot fully account for the variability of the Pb isotopic data using the identified crustal end......-members. The crustal anatectic end-member, although similar in Sr and Nd isotope composition, has a markedly different Pb isotopic composition than its source gneiss. The differences are consistent with preferential incorporation of radiogenic Pb from accessory phases such as metamict zircon or loosely-bound Pb from...

  3. Exposure to mixtures of organohalogen contaminants and associative interactions with thyroid hormones in East Greenland polar bears (Ursus maritimus)

    DEFF Research Database (Denmark)

    Villanger, Gro D.; Jenssen, Bjørn M.; Fjeldberg, Rita R.

    2011-01-01

    We investigated the multivariate relationships between adipose tissue residue levels of 48 individual organohalogen contaminants (OHCs) and circulating thyroid hormone (TH) levels in polar bears (Ursus maritimus) from East Greenland (1999–2001, n=62), using projection to latent structure (PLS......) regression for four groupings of polar bears; subadults (SubA), adult females with cubs (AdF_N), adult females without cubs (AdF_S) and adult males (AdM). In the resulting significant PLS models for SubA, AdF_N and AdF_S, some OHCs were especially important in explaining variations in circulating TH levels...... that influenced TH levels in the significant PLS models may potentially act through similar mechanisms on the hypothalamic–pituitary–thyroid (HPT) axis, suggesting that both combined effects by dose and response addition and perhaps synergistic potentiation may be a possibility in these polar bears. Statistical...

  4. Multi-decadal record of ice dynamics on Daugaard Jensen Gletscher, East Greenland, from satellite imagery and terrestrial measurements

    DEFF Research Database (Denmark)

    Stearns, L.A.; Hamilton, G.S.; Reeh, Niels

    2005-01-01

    The history of ice velocity and calving front position of Daugaard Jensen Gletscher, a large outlet glacier in East Greenland, is reconstructed from field measurements, aerial photography and satellite imagery for the period 1950-2001. The calving terminus of the glacier has remained...... in approximately the same position over the past similar to 50 years. There is no evidence of a change in ice motion between 1968 and 2001, based on a comparison of velocities derived from terrestrial surveying and feature tracking using sequential satellite images. Estimates of flux near the entrance to the fjord...... vs snow accumulation in the interior catchment show that Daugaard Jensen Gletscher has a small negative mass balance. This result is consistent with other mass-balance estimates for the inland region of the glacier....

  5. Sediment thicknesses and holocene glacial marine sedimentation rates in three east Greenland fjords (ca. 68°N)

    Science.gov (United States)

    Andrews, J.T.; Milliman, John D.; Jennings, A.E.; Rynes, N.; Dwyer, J.

    1994-01-01

    We compared measured and estimated sediment budgets in heavily glaciated fjords in East Greenland. Mass balance calculations and regional glacio-climatic conditions suggest that the sediment flux to the seafloor in Kangerdlugssuaq and Nansen fjords should be dominated by iceberg rafting and not by the rain-out of suspended particulates in meltwater, as the glacier calving flux is estimated at 15 and $2 km^{3}/yr$, compared to meltwater volumes of 4.4 and $1.7 km^{3}/yr$, respectively. Gravity cores in the three fjords indicate that the uppermost 1-2.5 m of sediment consists of diamictons or fine-grained laminated muds. AMS radiocarbon dates on calcareous foramininfera or shells (16 total) indicate sedimentation rates of 110 to 340 cm/ka within the fjords over the last 1 ka, and 10-20 cm/ka during the Holecene on the inner and middle shelf. Annual sediment discharge is around $0.67 \\times 10^{6}$ tonnes/yr within the Kangerdlugssuaq Fjord and Trough system, which translates into an average basin-wide rate of denudation of 0.01 mm/yr (0.01 m/ka). Air gun and deep-towed (Huntec) seismic profiling was carried out in Kangerdlugssuaq and Nansen fjords, East Greenland, and showed that sediment fills averaged 500 and 350 m respectively; they consist primarily of acoustically stratified sediments. If the sediment fills are entirely Holocene in age then the required average sediment accumulation rates of 35-50 m/ka are an order of magnitude larger than the $^{14}C $controlled rates of the last 1-2 ka. This raises the possibility that fjord sediments may be by-passed and not always recycled during glacial advances; this will affect sedimentation rates on adjacent shelves and deep-sea areas during successive glaciations

  6. Three Paleoproterozoic A-type granite intrusions and associated dykes from Kainuu, East Finland

    Directory of Open Access Journals (Sweden)

    Hannu Huhma

    2010-12-01

    Full Text Available Mafic and felsic intrusive rocks aged 2.5–2.4 Ga have been observed over a large area in eastern and northern Finland, as well as in adjacent northwestern Russia. We describe three granite intrusions and associated dykes from Kainuu, Finland, that belong to this bimodal magmatic event. All these three granites show clear A2-type chemical affinities with high Y/Nb, HREE, Fe/Mg, Ga and Nb. Two of the intrusions, Rasinkylä and Pussisvaara, were dated at 2425±3 and 2427±3 Ma, respectively, using thermal ionisation mass spectrometry utilizing the chemical abrasion method (CA-TIMS. CA-TIMS ages are supported by single-grain age determinations obtained by using Laser Ablation Multicollector Inductively Coupled Plasma Mass Spectrometer (LA-MC-ICPMS. New data on the previously described Rasimäki granite from southern Kainuu is presented, including an age of 2389±5 Ma obtained with LA-MC-ICPMS. The variable magnetite content of the granites is proposed to reflect the differences in the oxidation state of the source, which in our interpretation is the local Archean lower crust. Partial melting and the emplacement of the granites occurred in an extensional environment. Heat for the partial melting was provided by mafic magmas under and intraplating the extended crust.

  7. Water temperature, conductivity, and currents data collected by CTDs and current meters on moored buoys in the Sermilik Fjord and Kangerdlugssuaq Glacier, in East Greenland from 2009-08 to 2012-09 (NCEI Accession 0127320)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data included in this dataset were collected in East Greenland in the Sermilik Fjord, located in the Ammassalik district close to the town of Tasiilaq and at the...

  8. Muskox site fidelity and group cohesion in Jameson Land, East Greenland

    DEFF Research Database (Denmark)

    Aastrup, P. J.

    2004-01-01

    Increasing hunting pressure in Greenland demands improved knowledge on Muskox (Ovibos moschatus) biology in general and movement and grouping behaviour in specific to insure their proper management. Improving the exchange of information between hunters and managers is also necessary. Muskox site...... fidelity and group cohesion was examined over a 16-year period using 477 earmarked individuals tagged in 1982 and 1983. Combining information from scientists and hunters, observations of live individuals were primarily made from 1983 to 1990, while the latest tagged muskoxen reported shot was from 1998...... that such cooperation can provide important information for management related to muskox harvesting and monitoring....

  9. Coastal glaciers advanced onto Jameson Land, East Greenland during the late glacial–early Holocene Milne Land Stade

    Directory of Open Access Journals (Sweden)

    Helena Alexanderson

    2014-01-01

    Full Text Available We report on 10Be and optically stimulated luminescence ages from moraines and glaciolacustrine sediments on eastern Jameson Land, East Greenland. Sampled landforms and sediment are associated with advances of outlet glaciers from the local Liverpool Land ice cap situated in the coastal Scoresby Sund region. Previous studies have tentatively correlated these advances with the Milne Land Stade moraines, which are prominent moraine sets deposited by mountain glaciers in the inner Scoresby Sund region. Recent constraints on the formation of the outer and inner of these moraines have suggested two advances of local glaciers, one prior to or during the Younger Dryas and another during the Preboreal. In this paper, we test the correlation of the Liverpool Land glacial advance with the Milne Land Stade. Our results show that outlet glaciers from the Liverpool Land ice cap reached ice-marginal positions marked by moraines in east-facing valleys on Jameson Land sometime during late glacial–early Holocene time (ca. 13–11 Kya. This confirms the correlation of these moraines with the Milne Land Stade moraines described elsewhere in the Scoresby Sund region.

  10. Liquid freshwater transport estimates from the East Greenland Current based on continuous measurements north of Denmark Strait

    Science.gov (United States)

    de Steur, L.; Pickart, R. S.; Macrander, A.; Vâge, K.; Harden, B.; Jónsson, S.; Østerhus, S.; Valdimarsson, H.

    2017-01-01

    Liquid freshwater transports of the shelfbreak East Greenland Current (EGC) and the separated EGC are determined from mooring records from the Kögur section north of Denmark Strait between August 2011 and July 2012. The 11 month mean freshwater transport (FWT), relative to a salinity of 34.8, was 65 ± 11 mSv to the south. Approximately 70% of this was associated with the shelfbreak EGC and the remaining 30% with the separated EGC. Very large southward FWT ranging from 160 mSv to 120 mSv was observed from September to mid-October 2011 and was foremost due to anomalously low upper-layer salinities. The FWT may, however, be underestimated by approximately 5 mSv due to sampling biases in the upper ocean. The FWT on the Greenland shelf was estimated using additional inshore moorings deployed from 2012 to 2014. While the annual mean ranged from nearly zero during the first year to 18 mSv to the south during the second year, synoptically the FWT on the shelf can be significant. Furthermore, an anomalous event in autumn 2011 caused the shelfbreak EGC to reverse, leading to a large reduction in FWT. This reversed circulation was due to the passage of a large, 100 km wide anticyclone originating upstream from the shelfbreak. The late summer FWT of -131 mSv is 150% larger than earlier estimates based on sections in the late-1990s and early-2000s. This increase is likely the result of enhanced freshwater flux from the Arctic Ocean to the Nordic Seas during the early 2010s.

  11. Brain region-specific perfluoroalkylated sulfonate (PFSA) and carboxylic acid (PFCA) accumulation and neurochemical biomarker Responses in east Greenland polar Bears (Ursus maritimus)

    DEFF Research Database (Denmark)

    Pedersen, Kathrine Eggers; Basu, Niladri; Letcher, Robert

    2015-01-01

    to bioaccumulate in lipid rich tissues of the brain among other tissues such as liver, and can reach high concentrations in top predators including the polar bear. PFCA and PFSA bioaccummulation in the brain has the potential to pose neurotoxic effects and therefore we conducted a study to investigate...... if variations in neurochemical transmitter systems i.e. the cholinergic, glutaminergic, dopaminergic and GABAergic, could be related to brain-specific bioaccumulation of PFASs in East Greenland polar bears. Nine brain regions from nine polar bears were analyzed for enzyme activity (monoamine oxidase (MAO...... regions, whereas GS activity was positively correlated with PFASs primarily in occipital lobe. Results from the present study support the hypothesis that PFAS concentrations in polar bears from East Greenland have exceeded the threshold limits for neurochemical alterations. It is not known whether...

  12. Muskox site fidelity and group cohesion in Jameson Land, East Greenland

    DEFF Research Database (Denmark)

    Aastrup, P. J.

    2004-01-01

    Increasing hunting pressure in Greenland demands improved knowledge on Muskox (Ovibos moschatus) biology in general and movement and grouping behaviour in specific to insure their proper management. Improving the exchange of information between hunters and managers is also necessary. Muskox site...... fidelity and group cohesion was examined over a 16-year period using 477 earmarked individuals tagged in 1982 and 1983. Combining information from scientists and hunters, observations of live individuals were primarily made from 1983 to 1990, while the latest tagged muskoxen reported shot was from 1998....... Muskoxen in this area had a very loose group structure, with mother-young pairs as the only apparent bond between individuals. Furthermore, the tagged muskoxen lacked strong fidelity to the site where they were tagged and roamed within an 11.000-km2 area. Hunters reported tagged muskoxen shot up to 120 km...

  13. How unique is the Udachnaya-East kimberlite? Comparison with kimberlites from the Slave Craton (Canada) and SW Greenland

    Science.gov (United States)

    Kamenetsky, Vadim S.; Kamenetsky, Maya B.; Weiss, Yakov; Navon, Oded; Nielsen, Troels F. D.; Mernagh, Terrence P.

    2009-11-01

    The origin of alkali carbonates and chlorides in the groundmass of unaltered Udachnaya-East kimberlites in Siberia is still controversial. Contrary to existing dogma that the Udachnaya-East kimberlite was either contaminated by the crustal sediments or platform brines, magmatic origin of the groundmass assemblage has been proposed on the basis of melt immiscibility textures, melt inclusion studies, and strontium and neon isotope compositions. We further tested the idea of alkali- and chlorine enrichment of the kimberlite parental melt by studying olivine-hosted melt inclusions and secondary serpentine in kimberlites from the Slave Craton, Canada (Gahcho Kué, Jericho, Aaron and Leslie pipes) and southern West Greenland (Majuagaa dyke). Host olivine phenocrysts closely resemble groundmass olivine from the Udachnaya-East kimberlite in morphology, compositions (high-Fo, low-Ca), complex zoning with cores of varying shapes and compositions and rims of constant Fo. Melt inclusions in olivine consist of several translucent and opaque daughter phases and vapour bubble(s). The daughter crystals studied in unexposed inclusions by laser Raman spectroscopy and in carefully exposed inclusions by WDS-EDS are represented by Na-K chlorides, calcite, dolomite, magnesite, Ca-Na, Ca-Na-K and Ca-Mg-Ba carbonates, bradleyite Na 3 Mg(CO 3)(PO 4), K-bearing nahpoite Na 2(HPO 4), apatite, phlogopite and tetraferriphlogopite, unidentified sulphates, Fe sulphides, djerfisherite, pyrochlore (Na,Ca) 2Nb 2O 6(OH,F), monticellite, Cr-spinel and Fe-Ti oxides. High abundances of Na, K (e.g., (Na + K)/Ca = 0.15-0.85) and incompatible trace elements in the melt inclusions are confirmed by LA-ICPMS analysis of individual inclusions. Heating experiments show that melting of daughter minerals starts and completes at low temperatures (~ 100 °C and 600 °C, respectively), further reinforcing the similarity with the Udachnaya-East kimberlite. Serpentine minerals replacing olivine in some of the studied

  14. 3D textural evidence for the formation of ultra-high tenor precious metal bearing sulphide microdroplets in offset reefs: An extreme example from the Platinova Reef, Skaergaard Intrusion, Greenland

    Science.gov (United States)

    Holwell, David A.; Barnes, Stephen J.; Le Vaillant, Margaux; Keays, Reid R.; Fisher, Louise A.; Prasser, Richard

    2016-07-01

    The Platinova Reef in the Skaergaard Intrusion, east Greenland, is an example of a type of layered-intrusion-hosted, precious metal-enriched, stratiform, disseminated sulphide deposit referred to as "offset reefs". These typically show platinum-group element (PGE) enrichment immediately below a major increase in the abundance of Cu-rich sulphides, with a prominent peak in Au enrichment exactly at that transition between the PGE-rich and the Cu-sulphide-rich zones. The reasons for the relative sequence of offsets in metal peaks, and the occasionally very high metal tenors have been subject to great debate. Here we use an integrated approach of high-resolution X-ray computed tomography (HRXCT), SEM, synchrotron and desktop microbeam XRF mapping, and thin section petrography to comprehensively classify the textural relations of the precious metal-bearing sulphides of the Platinova Reef as an extreme end member example of an exceedingly high tenor offset deposit. Our results show that in the zones of PGE enrichment, precious metal minerals (PMMs) are intimately associated with Cu sulphide globules, mostly located at, or close to, silicate and oxide boundaries. The textures are identical in zones enriched in Pd and Au, and thus we do not see any evidence for different processes forming the different zones. The PMM:Cu sulphide ratio in each globule varies significantly but overall the size of the globules increases from the Pd-rich, through the Au-rich, and into the Cu zone, with a significant corresponding decrease in PM tenor. As such, this records a progression of exceedingly high tenor, microdroplets of sulphide, which progressively get larger up through the section, and decrease in tenor proportionally to their size. Cumulus droplets of Cu sulphide became enriched in metals, and were trapped in situ without significant transport from their point of nucleation. The transition to larger sulphides represents a change from sulphides nucleated and trapped in situ, to

  15. Ocean tides modulation of flow at Helheim Glacier, East Greenland, observed using GPS

    DEFF Research Database (Denmark)

    de Juan, Julia; Elosegui, P.; Nettles, M.;

    Observations at high spatial and temporal resolution could be key for improving our understanding of the physical processes that govern outlet-glacier flow variations. We collected simultaneous high-rate GPS observations at several locations distributed along and across Helheim Glacier, East Gree...

  16. Detection and Monitoring of New-Ice in the East Greenland Sea Using the SeaWinds Scatterometer

    Institute of Scientific and Technical Information of China (English)

    Robert Ezraty

    2002-01-01

    Space borne radar scatterometers are primarily designed to measure the wind vector over the world ocean; yetthey also provide useful information on sea ice type and extent. In this paper, it is shown how the SeaWinds scatterometercan be used to detect new sea ice at the very beginning of its growth. Taking advantage of the very good coverage of the EastGreenland Sea by SeaWinds on board the QuikSCAT satellite it has been possible to detect the early stage of formation of thesea ice peninsula, named the Odden, and to monitor its evolution during March 2001. The early sea ice detection has beenvalidated by using RADARSAT Synthetic Aperture Radar scenes. It is also shown that microwave radiometers, such as theSpecial Sensor Microwave Imager (SSM/I), which are used as standard sensors for sea ice monitoring, do not detect the veryearly stage of sea ice growth and lag behind new sea ice occurrence by about twelve to twenty four hours.

  17. Relationships between stylolites and cementation in sandstone reservoirs: Examples from the North Sea, U.K. and East Greenland

    Science.gov (United States)

    Baron, Martin; Parnell, John

    2007-01-01

    The reservoir potential of hydrocarbon sandstone reservoirs may be significantly reduced by compartmentation as a result of the development of stylolites. A petrographic and fluid inclusion microthermometric study was performed on sandstones containing abundant stylolites from the Buchan, Galley and Scott Fields in the Outer Moray Firth, offshore Scotland, and from a palaeo-oil bearing sequence in East Greenland. The main objective of this study was to further constrain the temperatures and burial depths at which stylolitization occurs in sandstone reservoirs. The sandstones containing abundant stylolites are also characterized by their highly cemented nature. Numerous occurrences of quartz overgrowths clearly truncated by sutured stylolites are evident in all of the samples. Fluid inclusion microthermometry reveals that quartz cementation, which is interpreted to be coeval with stylolitization, occurred at minimum temperatures of between 86 and 136 °C. Basin modelling of the Scott and Galley Fields indicates that quartz cementation and stylolite development formed at depths greater than 2.5 km which were attained during rapid Tertiary burial. The occurrence of hydrocarbon fluid inclusions within healed microfractures orientated at high angles to the stylolites suggests that these microfractures provided pathways for hydrocarbon migration in the highly cemented, low permeability zones associated with highly stylolitized sandstones.

  18. Response of the large-scale subglacial drainage system of North East Greenland to surface elevation changes

    Directory of Open Access Journals (Sweden)

    N. B. Karlsson

    2015-01-01

    Full Text Available The influence of subglacial water on the dynamics of ice flow has been the object of increasing interest in the past decade. In this study we focus on large-scale, long-term changes in surface elevation over North East Greenland, and the corresponding changes in subglacial water routes. Our results show that over time-scales ranging from decades to millennia the area may experience redistribution of and fluctuation in subglacial water outflux under the main glacier outlets. The fluctuations in subglacial water routing occur even in the absence of external forcing. Based on these results we conclude that changes in the subglacial water routes are an intrinsic part of the drainage basin dynamics, where the subglacial system is likely always in a transient state. The results also imply that fluctuations at the margins observed at present might originate from changes several hundred kilometres upstream. Since surface elevation changes may propagate upstream over time-scales much longer than the observational period, the cause of the fluctuations may not be present in current observational records.

  19. At-sea observations of the spring migration and pair bonding of ivory gulls (Pagophila eburnea around Svalbard and East Greenland

    Directory of Open Access Journals (Sweden)

    Henrik Kylin

    2011-03-01

    Full Text Available Because of logistical constraints little previous information exists on ivory gulls (Pagophila eburnea in the waters around Svalbard and the east coast of Greenland in late winter/early spring. The Swedish Arctic Ocean 2002 expedition investigated these areas at that time of year and in this paper I report on the observations of ivory gulls made during the expedition. The ivory gull was essentially absent from open waters but was the most common seabird in areas with pack ice, showing behavioural differences depending on local conditions. Generally, the number of ivory gulls was low when there was little plankton in the water. Ivory gulls followed the ship depending on the availability of food items in the wake and also depending on competition from other species, particularly glaucous gulls (Larus hyperboreus. Although ivory gulls were present in most of Fram Strait and the northern part of the East Greenland Current during 6 and 19 May, sightings were few and correlated to the amount of plankton in the water. Aggregations of several hundred were seen on the ice where copulation and other social interaction took place. A previously undescribed pair bonding behaviour during which females seemed to select between two competing males was observed north of Svalbard on 30 April–1 May. Off Scoresby Sound on 25 May, more than 700 birds were seen migrating north, while farther south along the Greenland coast on 30 May there was little indication of migration although many ivory gulls were seen.

  20. Tracing Mycobacterium tuberculosis transmission by whole genome sequencing in a high incidence setting: a retrospective population-based study in East Greenland

    Science.gov (United States)

    Bjorn-Mortensen, K.; Soborg, B.; Koch, A.; Ladefoged, K.; Merker, M.; Lillebaek, T.; Andersen, A. B.; Niemann, S.; Kohl, T. A.

    2016-01-01

    In East Greenland, a dramatic increase of tuberculosis (TB) incidence has been observed in recent years. Classical genotyping suggests a genetically similar Mycobacterium tuberculosis (Mtb) strain population as cause, however, precise transmission patterns are unclear. We performed whole genome sequencing (WGS) of Mtb isolates from 98% of culture-positive TB cases through 21 years (n = 182) which revealed four genomic clusters of the Euro-American lineage (mainly sub-lineage 4.8 (n = 134)). The time to the most recent common ancestor of lineage 4.8 strains was found to be 100 years. This sub-lineage further diversified in the 1970s, and massively expanded in the 1990s, a period of lowered TB awareness in Greenland. Despite the low genetic strain diversity, WGS data revealed several recent short-term transmission events in line with the increasing incidence in the region. Thus, the isolated setting and the uniformity of circulating Mtb strains indicated that the majority of East Greenlandic TB cases originated from one or few strains introduced within the last century. Thereby, the study shows the consequences of even short interruptions in TB control efforts in previously TB high incidence areas and demonstrates the potential role of WGS in detecting ongoing micro epidemics, thus guiding public health efforts in the future. PMID:27615360

  1. The interglacial-glacial record at the mouth of Scoresby Sund, East Greenland

    DEFF Research Database (Denmark)

    Mangerud, Jan; Funder, Svend Visby

    1994-01-01

    The sedimentary record around outer Scoresby Sund begins with the Scoresby Sund glaciation ( "" isotope stage 6), but is incomplete. Both at Kap Hope, seadward of the fjord mouth, and at Kikiakajik on the outer coast, there are shallow marine sediments, correlated with the Langelandselv interglac......The sedimentary record around outer Scoresby Sund begins with the Scoresby Sund glaciation ( "" isotope stage 6), but is incomplete. Both at Kap Hope, seadward of the fjord mouth, and at Kikiakajik on the outer coast, there are shallow marine sediments, correlated with the Langelandselv...... stade ( "" 19-15 ka BP) when, from marine geological data, it is suggested that the Scoresby Sund glacier terminated c. 30 km east of Kap Brewster. During the Milne Land stade (c. 10 ka BP) there was a resurgence of local ice caps in the mountains both north and south of the fjord mouth, but Scoresby...

  2. High-Resolution Monitoring of Glacier Dynamics During Calving Events at Helheim Glacier South-East Greenland

    Science.gov (United States)

    Murray, T.; Rutt, I. C.; O'Farrell, T.; Edwards, S.; Selmes, N.; Martin, I.; James, T.; Aspey, R.; Bevan, S. L.; Loskot, P.; Baugé, T.

    2013-12-01

    By bringing together expertise in glaciology, GNSS (Global Navigation Satellite System) technology and processing, and wireless networks we have designed, installed and operated a wireless network of GNSS sensors very close to the margin of the heavily crevassed and fast-flowing Helheim Glacier in south-east Greenland. In 2012, we undertook field trials installing 3 GNSS sensors on the glacier's flowline, and observed the dynamic effects of a major calving event. In 2013, a full 20 node wireless network was installed together with 5 oblique cameras, instrumenting an area ~16 km^2 of the glacier margin. The network will run throughout the summer months. In combination with auxiliary data, such as airborne lidar measurement of surface topography, crevasse spacing and calving rates, oblique photogrammetry, and DEMs and velocity fields from TanDEM-X satellite imagery, the network provides velocity and elevation data of unprecedented resolution in time and space for the key marginal area of the glacier, where recent changes in glacier dynamics appear to have initiated. We present data showing the glacier's dynamic and topographic response to calving events. These data will provide rich opportunities for testing calving models and to improve understanding of the controls on the contribution of these tidewater glaciers to sea-level rise. The network has low energy consumption and a novel base-station topology providing diversity and redundancy: it is also robust to the loss of nodes as the glacier calves. Such a network would also be suitable for data collection in a number of harsh environmental settings such as earthquake, landslide or volcano monitoring.

  3. The endocrine disruption properties of an adipose contaminant mixture extracted from East Greenland polar bears studied in the H295R cell line

    DEFF Research Database (Denmark)

    Hjorth, R.; Letcher, R. J.; Blair, D.

    been well described and especially the polar bear (Ursus maritimus) is recognized as being one of the most contaminated species in the Arctic. The present study investigated the in vitro endocrine disruptive effects of the POP mixture found in adipose tissue from 10 East Greenland polar bears collected...... (dehydroepiandrosterone and androstenedione). These results demonstrated comprehensive in vitro effects of POPs extracted from polar bear adipose tissue on key elements in the steroidogenesis, and identifies disruption of CYP17 activity as a mode of action. A POP-induced interference with CYP17 can potentially explain...... previously observed hormone levels in polar bears and could pose a risk to their reproductive health....

  4. Polyhalogenated compounds (PCBs, chlordanes, HCB and BFRs) in four polar bears (Ursus maritimus) that swam malnourished from East Greenland to Iceland.

    Science.gov (United States)

    Vetter, Walter; Gall, Vanessa; Skírnisson, Karl

    2015-11-15

    Levels of organohalogen compounds (PCBs, chlordane, PBB 153, PBDEs, HCB) were determined in adipose tissue, liver, kidney and muscle of four polar bears which swam and/or drifted to Iceland in extremely malnourished condition. Since the colonization in the 9th century polar bears have been repeatedly observed in Iceland. However, in recent years three of the animals have clearly left their natural habitat in poor condition in May or June, i.e. at the end of the major feeding season. The fourth bear is believed to have drifted with melting ice to North-Eastern Iceland in mid-winter. The concentrations of the POPs were within the range or higher than the typical concentrations measured in polar bears from the East Greenland population. In addition to the targeted compounds, we tentatively detected Dechlorane 602 and its potential hydrodechlorinated Cl11-metabolite in all samples. Moreover, a polychlorinated compound which partly co-eluted with PCB 209 was detected in all liver samples but not in adipose tissue, kidney or muscle. The mass spectrum of the potential metabolite did not allow determining its structure. Polar bears are good swimmers and can reach Iceland from the ice edge of East Greenland within a few days. Potential reasons for the swims are briefly discussed.

  5. The East Greenland Current and its impacts on the Nordic Seas: observed trends in the past decade

    OpenAIRE

    Rudels, B.; M. Korhonen; Budeus, G.; Beszczynska-Moller, A.; Schauer, U.; Nummelin, A.; Quadfasel, D.; Valdimarsson, H.

    2012-01-01

    For the past 30 years, it has been known that dense waters are created in the Arctic Ocean. However, before the late 1980s, observations indicated that Arctic Ocean deep waters only modified the deep water in the Greenland Sea, which was still thought of as the major source of dense water. In the mid-1990s, this picture began to fade. The deep convection in the Greenland Sea weakened and only Arctic Intermediate Water was formed. A deep salinity maximum was reinforced and a temperature max...

  6. Organohalogen concentrations and a gross and histologic assessment of multiple organ systems in East Greenland polar bears (Ursus maritimus)

    DEFF Research Database (Denmark)

    Sonne, C.

    subsistence hunters from Central East Greenland (69°00'N to 74°00'N)during 1999-2002. The present thesis exposes the first and most important results from this large multidisciplinary study of this material, and evaluates the possible connection between the relatively high levels of organohalogens...... to the relatively high levels of organohalogens. But, there was indications of strong relationships between various organohalogen compounds and skull mineral density indicating disruption of the bone mineral composition. The histopathological changes found in liver- and kidney tissue were a result of ageing......, infectious agents, season and meaby chronic exposure to organohalogens. These result fill out an existing knowledge gap in potential effects of environmental, organic contaminants on fluctuating asymmetry, bone mineral density and functional anatomy (histology) in the polar bear. In addition, the results may...

  7. Vitamins A and E in liver, kidney, and whole blood of East Greenland polar bears sampled 1994–2008: reference values and temporal trends

    DEFF Research Database (Denmark)

    Bechshoft, T.; Sonne, C.; Jakobsen, Jette;

    2015-01-01

    Vitamins A (retinol) and E (α-tocopherol) are dietary vitamins, essential for, e.g., growth and development, reproduction, and immune function. Persistent organic pollutants (POPs) have been found to be related to vitamin A and E metabolism. However, few investigations have been published...... on this health issue in polar bears (Ursus maritimus). The aim of this study was thus to provide reference values for concentrations of vitamin A in liver, kidney cortex, and whole blood and vitamin E in kidney cortex and whole blood from 166 East Greenland polar bears, as well as to assess the relationship...... between POPs and vitamin concentrations. In addition, vitamin concentrations were analyzed for temporal trends (1994–2008). Results showed vitamin A in liver to be higher in adult bears and the concentrations of vitamin E in kidney and blood to likewise be generally higher in adult bears. In addition, all...

  8. Reproductive performance in East Greenland polar bears (Ursus maritimus) may be affected by organohalogen contaminants as shown by physiologically-based pharmacokinetic (PBPK) modelling

    DEFF Research Database (Denmark)

    Sonne, Christian; Gustavson, Kim; Rigét, Frank F.

    2009-01-01

    quotient (RQ) evaluation to more quantitatively evaluate the effect risk on reproduction (embryotoxicity and teratogenicity) based on the critical body residue (CBR) concept and using a physiologically-based pharmacokinetic (PBPK) model. We applied modelling approaches to PCBs, p,p′-DDE, dieldrin......, oxychlordane, HCHs, HCB, PBDEs and PFOS in East Greenland polar bears based on known OHC pharmacokinetics and dynamics in laboratory rats (Rattus rattus). The results showed that subcutaneous adipose tissue concentrations of dieldrin (range: 79–1271 ng g−1 lw) and PCBs (range: 4128–53 923 ng g−1 lw) reported...... and for dieldrin (range: 43–640 ng g−1 lw), PCBs (range: 3491–13 243 ng g−1 lw) and PFOS (range: 1332–6160 ng g−1 ww) in the year 2006. The concentrations of oxychlordane, DDTs, HCB and HCHs in polar bears resulted in RQs

  9. Alteration of Eudialyte and implications for the REE, ZR, and NB resources of the layered Kakortokites in the ILÍMAUSSAQ intrusion, South West Greenland

    DEFF Research Database (Denmark)

    Borst, Anouk Margaretha; Waight, Tod Earle; Smit, Matthijs Arjen

    2014-01-01

    with late‐stage magmatic, presumably Na‐ and F‐ rich aqueous fluids. The alteration effectively fractionates the major components into the secondary minerals, producing separate Zr‐, Nb and REE‐ phases, leading to an increased complexity of the mineralisation and potential ore recovery.......The layered kakortokites in the southern part of the Ilímaussaq Intrusion are of great economic interest due to their high concentrations of REE, Zr, Nb and Ta. The prospective metals are largely contained in eudialyte, a complex sodium‐zirconosilicate and one of the major cumulus phases. Eudialyte......‐group minerals are easily extracted from the host rock through magnetic separation, and contain 12 wt% ZrO2, 2 % TRE2O3 and 1% Nb2O5 on average. Petrographic investigations show that a large fraction of eudialyte at Ilímaussaq is replaced by complex aggregates of secondary minerals as a result of interaction...

  10. Evidence for regional cooling, frontal advances, and East Greenland Ice Sheet changes during the demise of the last interglacial

    Science.gov (United States)

    Irvalı, Nil; Ninnemann, Ulysses S.; Kleiven, Helga (Kikki) F.; Galaasen, Eirik V.; Morley, Audrey; Rosenthal, Yair

    2016-10-01

    High-resolution lithic and sea surface climate records are used to portray the progression of North Atlantic climate, hydrography, and Greenland Ice Sheet (GIS) activity through the peak of Marine Isotope Stage (MIS) 5e into the last glacial inception. We use Eirik Drift sediment core MD03-2664 (57°26.34‧N, 48°36.35‧W), recovered south of Greenland, strategically located to monitor fluctuations in GIS extent and iceberg calving events. Our results show that a significant amount of ice-rafted debris (IRD) was present during the early MIS 5e, until gradually tapering off by 122 kyr BP due to a diminishing GIS. Sea surface temperatures (SSTs) in the northern subpolar gyre reached peak values early in MIS 5e coinciding with peak insolation. Regional cooling leading to the demise of the last interglacial started prior to the end of the MIS 5e benthic δ18O plateau, at approximately 119 kyr BP, as summer insolation waned. This gradual cooling trend is interrupted by an abrupt and brief cooling episode at ∼117 kyr BP. Increased IRD abundance during the 117 kyr BP cooling event suggests that regional ice sheet growth occurred prior to the end of the MIS 5e benthic δ18O plateau, and the major glacial inception. SSTs south of Greenland followed a two-step cooling during the glacial inception similar to the pattern observed across much of the North Atlantic and Europe. Benthic δ18O increases in parallel, suggesting that this two-step cooling is linked to a two-phased intensification of Northern Hemisphere glaciation.

  11. Possible Greenland

    DEFF Research Database (Denmark)

    2012-01-01

    Organizing in Greenland is a complex matter. We have been on an arctic odyssey exploring the different aspects of the Greenlandic reality and have created a publication in which a wide range of Greenlandic and international profiles and stakeholders give their opinion and visions for the future...... development in Greenland. By creating a platform for a wide range of ideas about the Possible Greenland to be discussed now and in the future, we give Greenlanders and Greenlandic decision makers access to the greatest amount of possible solutions to the challenges they are facing. We look more closely...... at Greenland's structure, and ask some threshold questions. Which aspects of society are rooted in our human hardware? And, if we had the rare opportunity to build a new nation, what would we choose for ourselves? We hope this will inspire an open, imaginative and thoroughly human discussion about how...

  12. Holocene changes in climate and vegetation in the Ammassalik area, East Greenland, recorded in lake sediments and soil profiles

    DEFF Research Database (Denmark)

    Jakobsen, Bjarne Holm; Fredskild, Bent; Pedersen, Jørn Bjarke Torp

    2008-01-01

    Holocene climatic, vegetational and environmental changes on the Ammassalik Island in SE Greenland (65.5 N and 37.5 W) have been studied in lake sediments and soil profiles. Based on the stratigraphy of sediments, geobiochemical characteristics, pollen and other biological proxies, a history....... Generally decreasing insolation, a still colder landscape and near coastal sea, potentially further cooled by the negative albedo feedback from snow and ice, generally increase a gradient driven circulation of heat and moisture northwards in the western part of the North Atlantic. Counteracting...

  13. Envisioning Greenland

    DEFF Research Database (Denmark)

    Ren, Carina Bregnholm

    2012-01-01

    Currently, the traditional ‘cool’ representation of Greenland as a frozen landscape devoid of people and human structures is being challenged by an emerging vision of Greenland as ‘hot’. This article presents and describes these two versions of Greenland, showing how demarcations of what is ‘nature...

  14. Possible Greenland

    DEFF Research Database (Denmark)

    2012-01-01

    Organizing in Greenland is a complex matter. We have been on an arctic odyssey exploring the different aspects of the Greenlandic reality and have created a publication in which a wide range of Greenlandic and international profiles and stakeholders give their opinion and visions for the future d...

  15. Tidal Modulation of Ice Flow on Kangerdlugssuaq and Helheim Glaciers, East Greenland, from High-Rate GPS Measurements

    DEFF Research Database (Denmark)

    Hamilton, G. S.; Stearns, L. A.; Elosegui, P.

    Boundary conditions at the frontal margins of tidewater glaciers provide important constraints on the balance of forces affecting ice flow and iceberg calving. For many large outlet glaciers in Greenland, the type of boundary condition (floating vs grounded ice) is not well known, owing to limited...... periods of 2-5 days in July 2005, and June, July and August 2006. The data were post-processed using a Kalman predictive filter to yield epoch-by-epoch station positions and elevations. Modeled ocean tides are shown to have good agreement with the tide stage measured over ~~3 weeks in July-August 2006...... in Sermilik fjord, close to the terminus of Helheim Glacier. An analysis of ice vertical displacement and modeled ocean tide for Kangerdlugssuaq Glacier indicates the calving terminus was likely at near-flotation in July 2005. A tidal amplitude of ~~2.5 m produced an uplift of ~~2 m...

  16. Discussion on final rifting evolution and breakup : insights from the Mid Norwegian - North East Greenland rifted system

    Science.gov (United States)

    Peron-Pinvidic, Gwenn; Terje Osmundsen, Per

    2016-04-01

    In terms of rifted margin studies, the characteristics of the distal and outer domains are among the today's most debated questions. The architecture and composition of deep margins are rarely well constrained and hence little understood. Except from in a handful number of cases (eg. Iberia-Newfoundland, Southern Australia, Red Sea), basement samples are not available to decipher between the various interpretations allowed by geophysical models. No consensus has been reached on the basement composition, tectonic structures, sedimentary geometries or magmatic content. The result is that non-unique end-member interpretations and models are still proposed in the literature. So, although these domains mark the connection between continents and oceans, and thus correspond to unique stages in the Earth's lithospheric life cycle, their spatial and temporal evolution are still unresolved. The Norwegian-Greenland Sea rift system represents an exceptional laboratory to work on questions related to rifting, rifted margin formation and sedimentary basin evolution. It has been extensively studied for decades by both the academic and the industry communities. The proven and expected oil and gas potentials led to the methodical acquisition of world-class geophysical datasets, which permit the detailed research and thorough testing of concepts at local and regional scales. This contribution is issued from a three years project funded by ExxonMobil aiming at better understanding the crustal-scale nature and evolution of the Norwegian-Greenland Sea. The idea was to take advantage of the data availability on this specific rift system to investigate further the full crustal conjugate scale history of rifting, confronting the various available datasets. In this contribution, we will review the possible structural and sedimentary geometries of the distal margin, and their connection to the oceanic domain. We will discuss the definition of 'breakup' and introduce a first order conceptual

  17. Future vegetation patterns and primary production in the coastal wetlands of East China under sea level rise, sediment reduction, and saltwater intrusion

    Science.gov (United States)

    Ge, Zhen-Ming; Cao, Hao-Bin; Cui, Li-Fang; Zhao, Bin; Zhang, Li-Quan

    2015-10-01

    To explore the effects of sea level rise (SLR), sediment reduction (SR), and saltwater intrusion (SWI) on the vegetation patterns and primary production of one exotic (Spartina alterniflora) and two native dominant (Scirpus mariqueter and Phragmites australis) species in the coastal wetlands of East China, range expansion monitoring and stress experiments were conducted, followed by model prediction. After a rapid invasion period, the expansion rate of S. alterniflora slowed down due to the decreasing availability of suitable habitat under prolonged inundation. SLR was shown to decrease the colonization of S. alterniflora and the native P. australis up to 2100. In contrast, the native S. mariqueter that has a high tolerance of inundation increased in area following SLR, due to a reduction in competition from S. alterniflora in low-lying habitats and even recolonized areas previously invaded by the exotic species. The combination of SLR and SR resulted in further degradation of S. alterniflora and P. australis, while the area of S. mariqueter was not reduced significantly. The decrease in the area of vegetation would reduce the gross primary production under SLR and SR. SWI exacerbates the impacts, especially for P. australis, because S. alterniflora and S. mariqueter have a higher tolerance of salinity. Thus, the coastal vegetation pattern was predicted to be modified due to species-specific adaption to changed geophysical features. This study indicated that the native species better adapted to prolonged inundation and increased salinity might once again become key contributors to primary production on the muddy coasts of East China.

  18. Precambrian crustal evolution and Cretaceous–Palaeogene faulting in West Greenland: Pre-Nagssugtoqidian crustal evolution in West Greenland: geology, geochemistry and deformation of supracrustal and granitic rocks north-east of Kangaatsiaq

    Directory of Open Access Journals (Sweden)

    Watt, Gordon R.

    2006-12-01

    Full Text Available The area north-east of Kangaatsiaq features polyphase grey orthogneisses, supracrustal rocks and Kangaatsiaq granite exposed within a WSW–ENE-trending synform. The supracrustal rocks are comprised of garnet-bearing metapelites, layered amphibolites and layered, likewise grey biotite paragneisses. Their association and geochemical compositions are consistent with a metamorphosed volcano-sedimentary basin (containing both tholeiitic and calc-alkali lavas and is similar to other Archaean greenstone belts. The Kangaatsiaq granite forms a 15 × 3 km flat, subconcordant body of deformed,pink, porphyritic granite occupying the core of the supracrustal synform, and is demonstrably intrusive into the amphibolites. The granite displays a pronounced linear fabric (L or L > S. Thepost-granite deformation developed under lower amphibolite facies conditions (400 ± 50°C, and is characterised by a regular, NE–SW-trending subhorizontal lineation and an associated irregular foliation, whose poles define a great circle; together they are indicative of highly constrictional strain. The existence of a pre-granite event is attested by early isoclinal folds and a foliation within the amphibolites that is not present in the granite, and by the fact that the granite cuts earlier structures in the supracrustal rocks. This early event, preserved only in quartz-free lithologies, resulted in high-temperature fabrics being developed under upper amphibolite to granulite facies conditions.

  19. Fluorian garnets from the host rocks of the Skaergaard intrusion: implications for metamorphic fluid composition

    Science.gov (United States)

    Manning, C.E.; Bird, D.K.

    1990-01-01

    Zoned, silica-deficient, calcic garnets containing up to 5 mol% F substitution for O formed during contact metamorphism of basalts by the Skaergaard intrusion in East Greenland. Fluorian calcic garnets occur as a retrograde alteration of prograde wollastonite and clinopyroxene that fills vesicles and vugs in lavas 30-70 m from the intrusion. The F content of garnet is extremely sensitive to minor changes in fluid composition. The calculations show that a decrease in pH or an increase in log aF- of 0.3 at constant pressure and temperature will decrease the F concentration in garnet from 5 to 0 mol%. The results of this study show that fluorian hydrous grandites provide a mineralogical record of the activities of F species in coexisting metamorphic and hydrothermal fluids. -from Authors

  20. Oxygen-isotope exchange and mineral alteration in gabbros of the Lower Layered Series, Kap Edvard Holm Complex, East Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Fehlhaber, K.; Bird, D.K. (Stanford Univ., CA (United States))

    1991-08-01

    Multiple intrusions of gabbros, mafic dikes, and syenites in the Kap Edvard Holm Complex gave rise to prolonged circulation of meteoric hydrothermal solutions and extreme isotope exchange and mineral alteration in the 3,600-m-thick Lower Layered Series gabbros. In the Lower Layered Series, {delta}{sup 18}O of plagioclase varies from +0.3{per thousand} to {minus}5.8{per thousand}, and it decreases with an increase in the volume of secondary talc, chlorite, and actinolite. In the same gabbros, pyroxenes have a more restricted range in {delta}{sup 18}O, from 5.0{per thousand} to 3.8{per thousand}, and values of {delta}{sup 18}O{sub pyroxene} are independent of the abundance of secondary minerals, which ranges from 14% to 30%. These relations indicate that large amounts of water continued to flow through the rocks at temperatures of < 500-600C, altering the gabbros to assemblages of talc + chlorite + actinolite {plus minus}epidote {plus minus}albite and causing significant oxygen-isotope exchange in plagioclase, but not in pyroxene. The extensive low-temperature secondary mineralization and {sup 18}O depletion of plagioclase in the Lower Layered Series are associated with the later emplacement of dikes and gabbros and syenites, which created new fracture systems and provided heat sources for hydrothermal fluid circulation. This produced subsolidus mineral alteration and isotope exchange in the Lower Layered Series that are distinct from those in the Skaergaard and Cuillin gabbros of the North Atlantic Tertiary province, but are similar to those observed in some oceanic gabbros.

  1. Stratigraphy and sedimentology of a basement-onlapping shallow marine sandstone succession, the Charcot Bugt Formation, Middle-Upper Jurassic, East Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, M.; Piasecki, S. [Geological Survey of Denmark and Greenland, Copenhagen (Denmark)]. Geocenter; Surlyk, F. [Univ. of Copenhagen, Copenhagen (Denmark)]. Geological Inst.

    2003-07-01

    A rocky shore developed in early Middle Jurassic times by transgression of the crystalline basement in Milne'Land at the western margin of the East Greenland rift basin. The basement is onlapped by shallow marine sandstones of the Charcot Bugt Formation, locally with a thin fluvial unit at the base. The topography of the onlap surface suggests that a relative sea-level rise of at least 300 m took place in Early Bathonian - Middle Oxfordian times. The sea-level rise was punctuated by relative stillstands and falls during which progradation of the shoreline took place. Palynological data tied to the Boreal ammonite stratigraphy have greatly improved time resolution within the Charcot Bugt Formation, and the Jurassic succession in Milne Land can now be understood in terms of genetically-related depositional systems with a proximal to distal decrease in grain size. The sequence stratigraphic interpretation suggests that translation of the depositional systems governed by relative sea-level changes resulted in stacking of sandstone-dominated falling stage deposits in the Bastern, basinwards parts of Milne Land, whereas thick, remarkably coarsegrained transgressive systems tract deposits formed along the western basin margin. The bulk of the Charcot Bugt Formation consists of stacked sandstone-dominated shoreface units that prograded during highstands. The overall aggradational to backstepping stacking pattem recognised in the Charcot Bugt Formation is comparable to that in the contemporaneous Pelion Formation of the Jameson Land Basin and in correlative units of the mid-Norway shelf and the Northern North Sea. We suggest that the long-term evolution of the depositional systems may have been controlled by long-term eustatic rise acting in concert with relative sea-level changes reflecting regionally contemporaneous phases of rift initiation, dimax and gradual cessation of rifting. (au)

  2. The Late Cretaceous Middle Fork caldera, its resurgent intrusion, and enduring landscape stability in east-central Alaska

    Science.gov (United States)

    Bacon, Charles R.; Dusel-Bacon, Cynthia; Aleinikoff, John N.; Slack, John F.

    2014-01-01

    Dissected caldera structures expose thick intracaldera tuff and, uncommonly, cogenetic shallow plutons, while remnants of correlative outflow tuffs deposited on the pre-eruption ground surface record elements of ancient landscapes. The Middle Fork caldera encompasses a 10 km × 20 km area of rhyolite welded tuff and granite porphyry in east-central Alaska, ∼100 km west of the Yukon border. Intracaldera tuff is at least 850 m thick. The K-feldspar megacrystic granite porphyry is exposed over much of a 7 km × 12 km area having 650 m of relief within the western part of the caldera fill. Sensitive high-resolution ion microprobe with reverse geometry (SHRIMP-RG) analyses of zircon from intracaldera tuff, granite porphyry, and outflow tuff yield U-Pb ages of 70.0 ± 1.2, 69.7 ± 1.2, and 71.1 ± 0.5 Ma (95% confidence), respectively. An aeromagnetic survey indicates that the tuff is reversely magnetized, and, therefore, that the caldera-forming eruption occurred in the C31r geomagnetic polarity chron. The tuff and porphyry have arc geochemical signatures and a limited range in SiO2 of 69 to 72 wt%. Although their phenocrysts differ in size and abundance, similar quartz + K-feldspar + plagioclase + biotite mineralogy, whole-rock geochemistry, and analytically indistinguishable ages indicate that the tuff and porphyry were comagmatic. Resorption of phenocrysts in tuff and porphyry suggests that these magmas formed by thermal rejuvenation of near-solidus or solidified crystal mush. A rare magmatic enclave (54% SiO2, arc geochemical signature) in the porphyry may be similar to parental magma and provides evidence of mafic magma and thermal input.

  3. Avoidable deaths in Greenland 1968-1985

    DEFF Research Database (Denmark)

    Bjerregaard, Peter; Juel, K

    1990-01-01

    and several showed an increasing time trend. The regional patterns were particularly clear for infectious diseases and accidents, which showed low mortality rates in the capital and other towns and high mortality rates in settlements and in the remote East Greenland, while mortality rates from suicides...... and political will of the society. A list of avoidable deaths is proposed for Greenland which includes, inter alia, meningitis, lung cancer, acute respiratory infections, suicides, boat accidents and alcohol related diseases and accidents. All were considerably more common in Greenland than in Denmark...... and alcohol related diseases were high in the capital and East Greenland and low in West Greenlandic settlements. It is concluded that further studies on preventable diseases and causes of death, in particular certain infectious diseases, accidents and suicides, are needed....

  4. South Greenland

    DEFF Research Database (Denmark)

    This report is a preliminary strategic environmental impact assessment of activities related to exploration, development and exploitation of oil in the Greenland sector of the Labrador Sea and the southeast Davis Strait......This report is a preliminary strategic environmental impact assessment of activities related to exploration, development and exploitation of oil in the Greenland sector of the Labrador Sea and the southeast Davis Strait...

  5. Migration and breeding biology of arctic terns in Greenland

    DEFF Research Database (Denmark)

    Egevang, Carsten

    (Sandøen) in high-Arctic Northeast Greenland. The level of knowledge of the Arctic tern in Greenland before 2002 was to a large extent poor, with aspects of its biology being completely unknown in the Greenland population. This thesis presents novel findings for the Arctic tern, both on an international...... by the distribution of breeding Arctic terns as suggested by Egevang et al. (2004). Included in the thesis are furthermore results with an appeal to the Greenland management agencies. Along with estimates of the Arctic tern population size at the two most important Arctic tern colonies in West Greenland and East...

  6. High-resolution insights into episodes of crystallization, hydrothermal alteration and remelting in the Skaergaard intrusive complex

    Science.gov (United States)

    Wotzlaw, Jörn-Frederik; Bindeman, Ilya N.; Schaltegger, Urs; Brooks, C. Kent; Naslund, H. Richard

    2012-11-01

    This paper presents a new high-precision zircon U-Pb geochronological view on the crystallization and assembly process of one of the most important and intensely studied intrusive bodies on Earth—the Skaergaard intrusion in East Greenland. With analytical uncertainties of a few tens of thousands of years, we were able to resolve several important events during cooling of this intrusion. Initial cooling of the shallowly intruded ˜300 km3 of tholeiitic basaltic magma from liquidus to zircon saturation at ˜1000 °C is recorded by a precise zircon crystallization age of 55.960±0.018 Ma of an intercumulus gabbroic pegmatite in the lower portion of the intrusion. Based on this zircon crystallization age and a published cooling model we estimate the "true" age of emplacement to be ˜56.02 Ma. The last portions of Skaergaard appear to crystallize completely ˜100 ka after emplacement as recorded by abundant ˜55.91-55.93 Ma zircons in the Sandwich Horizon (SH), where lower and upper solidification fronts met. Intrusion of an isotopically distinct new magma batch, the ˜600 m thick Basistoppen Sill, into the solidified upper portion of Skaergaard, happened at 55.895±0.018 Ma, suggesting close timing between crystallization of evolved rocks around the SH and intrusion of the Basistoppen Sill. The novel result of this work is the demonstration that zircons in the SH, >100 m below the Basistoppen contact, have a bimodal age distribution, with the youngest population of 55.838±0.019 Ma postdating intrusion of the Basistoppen Sill by 57±37 ka. Oxygen isotope analyses reveal that SH zircons are low and heterogeneous with respect to δ18O. These results support the proposed conclusion that the SH crystallized twice: it was fully crystalline, then hydrothermally-altered by low-δ18O surface waters and subsequently partially remelted, triggered by heat of the Basistoppen Sill. The low-degree partial melt generated during remelting partially migrated upward by intergranular

  7. Growth of wild muskoxen under two nutritional regimes in Greenland

    DEFF Research Database (Denmark)

    Aastrup, Peter; Thing, Henning; Olesen, Carsten Riis

    1994-01-01

    Growth of muskoxen in Jameson Land, East Greenland (EG) and in Angujaartorfiup Nunaa, West Greenland (WG) is affected by the different nutritional conditions in the two areas. The abundance and availability of forage plants is highest in WG. Muskoxen in WG reach sexual maturity one year earlier...

  8. Life history parameters of narwhals (Monodon monoceros) from Greenland

    DEFF Research Database (Denmark)

    Garde, Eva; Hansen, Steen H; Ditlevsen, Susanne

    2015-01-01

    Life history parameters for narwhals (Monodon monoceros) were estimated based on age estimates from aspartic acid racemization of eye lens nuclei. Eyes, reproductive organs, and measures of body lengths were collected from 282 narwhals in East and West Greenland in the years 1993, 2004, and 2007...... projection matrix was parameterized with the data on age structure and fertility rates. The annual rate of increase of narwhals in East Greenland was estimated to be 3.8% while narwhals in West Greenland had a rate of increase at 2.6%. Key words:...

  9. MIZEX. A Program for Mesoscale Air-Ice-Ocean Interaction Experiments in Arctic Marginal Ice Zones. II. A Science Plan for a Summer Marginal Ice Zone Experiment in the Fram Strait/Greenland Sea: 1984.

    Science.gov (United States)

    1983-05-01

    salinity, southward-flowing East Greenland Current from the more saline water in the Greenland Sea; or more transient, such as ice edge meltwater fronts... meltwater fronts) in the Fram Strait and Greenland Sea marginal ice zones? What is their temporal and spatial variability over a period of days? What is...three-dimensional structure of the fronts (East Greenland polar front and meltwater fronts) in the Fram Strait- Greenland Sea MIZ, their short-period

  10. Using GPS and absolute gravity observations to separate the effects of present-day and Pleistocene ice-mass changes in South East Greenland

    Science.gov (United States)

    van Dam, T.; Francis, O.; Wahr, J.; Khan, S. A.; Bevis, M.; van den Broeke, M. R.

    2017-02-01

    Measurements of vertical crustal uplift from bedrock sites around the edge of the Greenland ice sheet (GrIS) can be used to constrain present day mass loss. Interpreting any observed crustal displacement around the GrIS in terms of present day changes in ice is complicated, however, by the glacial isostatic adjustment (GIA) signal. With GPS observations alone, it is impossible to separate the uplift driven by present day mass changes from that due to ice mass changes in the past. Wahr et al. (1995) demonstrated that viscoelastic surface displacements were related to the viscoelastic gravity changes through a proportionality constant that is nearly independent of the choice of Earth viscosity or ice history model. Thus, by making measurements of both gravity and surface motion at a bedrock site, the viscoelastic effects could be removed from the observations and we would be able to constrain present day ice mass changes. Alternatively, we could use the same observations of surface displacements and gravity to determine the GIA signal. In this paper, we extend the theory of Wahr et al. (1995) by introducing a constant, Z, that represents the ratio between the elastic changes in gravity and elastic uplift at a particular site due to present day mass changes. Further, we combine 20 yrs of GPS observations of uplift with eight absolute gravity observations over the same period to determine the GIA signal near Kulusuk, a site on the southeastern side of the GrIS, to experimentally demonstrate the theory. We estimate that the GIA signal in the region is 4.49 ± 1.44mm/yr and is inconsistent with most previously reported model predictions that demonstrate that the GIA signal here is negative. However, as there is very little in situ data to constrain the GIA rate in this part of Greenland, the Earth model or the ice history reconstructions could be inaccurate (Khan et al., 2016). Improving the estimate of GIA in this region of Greenland will allow us to better determine

  11. Basin-scale distribution of sill intrusions in the Tunguska Basin, East Siberia, and the implications for the end-Permian environmental crisis

    Science.gov (United States)

    Svensen, Henrik H.; Frolov, Sergei; Akhmanov, Grigorii G.; Polozov, Alexander G.; Planke, Sverre

    2015-04-01

    The emplacement of the Siberian Traps Large igneous province through the Tunguska Basin is regarded as the main processes behind the end-Permian environmental crisis. Still, the lack of data from the Tunguska Basin represents one of the main uncertainties in understanding this link. Degassing from contact metamorphic aureoles in evaporites is suggested as key to the continental mass extinction, but very little is known about the actual distribution of sills within these lithologies. We present results from a unique borehole database with more than 700 boreholes, where 293 boreholes are studied in detail and presented here. The boreholes cover large parts of the basin, from Norilsk in the north (N69) to Bratsk in the south (N55), with a bias towards petroleum-bearing regions. In total, 93.5% of the selected boreholes contain sill intrusions. The sill thicknesses vary considerably from kilometer-scale intrusive complexes to individual thin sills of a few tens of meters. Locally, thick sills (up to 900 meters in thickness) occur in the upper part of the sedimentary succession, affecting the coal-rich Tunguska Series sediments. However, on average, the thickest sills in the basin are emplaced within the vast Cambrian salt formations, with average thicknesses in the 115-130 meter range. Accompanying petrographic investigations of metamorphic sediments demonstrate that widespread high temperature devolatilization took place. Degassing to the atmosphere took place via explosive pipe degassing and seepage. We show that depending on the specific location within the province and the emplacement depth, the potential for degassing of both greenhouse gases (CH4, CO2), aerosols (SO2), and ozone destructive gases (CH3Cl, CH3Br) was substantial and can explain the end-Permian mass extinction.

  12. Parental magma of the Skaergaard intrusion: constraints from melt inclusions in primitive troctolite blocks and FG-1 dykes

    Science.gov (United States)

    Jakobsen, Jakob K.; Tegner, Christian; Brooks, C. Kent; Kent, Adam J. R.; Lesher, Charles E.; Nielsen, Troels F. D.; Wiedenbeck, Michael

    2010-01-01

    Troctolite blocks with compositions akin to the Hidden Zone are exposed in a tholeiitic dyke cutting across the Skaergaard intrusion, East Greenland. Plagioclase in these blocks contains finely crystallised melt inclusions that we have homogenised to constrain the parental magma to 47.4-49.0 wt.% SiO2, 13.4-14.9 wt.% Al2O3 and 10.7-14.1 wt.% FeOT. These compositions are lower in FeOT and higher in SiO2 than previous estimates and have distinct La/SmN and Dy/YbN ratios that link them to the lowermost volcanic succession (Milne Land Formation) of the regional East Greenland flood basalt province. New major- and trace element compositions for the FG-1 dyke swarm, previously taken to represent Skaergaard magmas, overlap with the entire range of the regional flood basalt succession and do not form a coherent suite of Skaergaard like melts. These dykes are therefore re-interpreted as feeder dykes throughout the main phase of flood basalt volcanism.

  13. The peopling of Greenland

    DEFF Research Database (Denmark)

    Pereira, Vania; Tomas Mas, Carmen; Sanchez, Juan J

    2015-01-01

    The peopling of Greenland has a complex history shaped by population migrations, isolation and genetic drift. The Greenlanders present a genetic heritage with components of European and Inuit groups; previous studies using uniparentally inherited markers in Greenlanders have reported evidence of ...

  14. Parental magma of the Skaergaard intrusion: constraints from melt inclusions in primitive troctolite blocks and FG-1 dykes

    OpenAIRE

    J. K. Jakobsen; C. Tegner; C. K. Brooks; A. J. R. Kent; C.-E. Lesher; T.F.D. Nielsen; Michael Wiedenbeck

    2010-01-01

    Troctolite blocks with compositions akin to the Hidden Zone are exposed in a tholeiitic dyke cutting across the Skaergaard intrusion, East Greenland. Plagioclase in these blocks contains finely crystallised melt inclusions that we have homogenised to constrain the parental magma to 47.4–49.0 wt.% SiO2, 13.4–14.9 wt.% Al2O3 and 10.7–14.1 wt.% FeOT. These compositions are lower in FeOT and higher in SiO2 than previous estimates and have distinct La/SmN and Dy/YbN ratios that link them to the lo...

  15. Geologic mapping in Greenland with polarimetric SAR

    DEFF Research Database (Denmark)

    Dall, Jørgen; Madsen, Søren Nørvang; Brooks, C. K.

    1995-01-01

    The application of synthetic aperture radar (SAR) for geologic mapping in Greenland is investigated by the Danish Center for Remote Sensing (DCRS) in co-operation with the Danish Lithosphere Centre (DLC). In 1994 a pilot project was conducted in East Greenland. The Danish airborne SAR, EMISAR......, acquired fully polarimetric C-band data which, upon processing and calibration, was interpreted jointly by DCRS and DLC. Several geologic phenomena are readily identified in the SAR imagery, while different lithologies seem to be indistinguishable because they have similar geomorphologies. The geologic...

  16. Important role of magma mixing in generating the Mesozoic monzodioritic-granodioritic intrusions related to Cu mineralization, Tongling, East China: Evidence from petrological and in situ Sr-Hf isotopic data

    Science.gov (United States)

    Chen, C. J.; Chen, B.; Li, Z.; Wang, Z. Q.

    2016-04-01

    The Mesozoic ore-bearing high-Mg monzodioritic-granodioritic rocks in the Tongling mining district (East China) have been described as having adakitic affinities, and their origin has been attributed to partial melting of delaminated eclogite at depth in the mantle, followed by interaction of the resultant granitic magma with mantle peridotite. Here we present petrological data and in situ Sr isotopic data for zoned plagioclase that are inconsistent with the eclogite-derived model and instead propose a model that involves magma mixing of siliceous crustal melts and basaltic magma that was derived from metasomatized mantle in a back-arc extensional regime. The principal geochemical signatures of these Mesozoic rocks include a high-K calc-alkaline affinity, high values of Mg#, high Sr-Ba abundances, high Sr/Y and La/Yb ratios, εNd(t) = - 13.1 to - 9.0, and ISr = 0.70707-0.70824. The magma mixing model is supported by (1) the common existence of mafic microgranular enclaves (MMEs) and the disequilibrium textures of plagioclase and amphibole, (2) the 87Sr/86Sr ratios of embayed high-Ca cores of plagioclase that are distinctly lower than in the euhedral low-Ca overgrowth rims, (3) the negative correlations between whole-rock Nd and Sr isotopic ratios, and (4) the significant differences in the values of εHf(t) (- 9.5 to - 26) within different zircons from the same intrusion.

  17. Petroleum Vapor Intrusion

    Science.gov (United States)

    One type of vapor intrusion is PVI, in which vapors from petroleum hydrocarbons such as gasoline, diesel, or jet fuel enter a building. Intrusion of contaminant vapors into indoor spaces is of concern.

  18. Popular music from Greenland

    DEFF Research Database (Denmark)

    Otte, Andreas Roed

    Popular music from Greenland – Globalization, nationalism and performance of place. This thesis is based on fieldwork done within the popular music scene in Greenland from 2008 to 2014. It engages with the question of how music and conceptions of the nation (Greenland) affect each other in social...... spaces, and analyses on how popular music can be used to construct senses of place and situate individuals within these places. The thesis is centered on four articles that engage with Greenlandic popular music from different perspectives. The first article looks at the historical development in inducing...... a sense of place in popular music. The second probes different strategies for co-branding popular music and Greenland. The third is concerned with music consumption patterns among Greenlandic youth. And the fourth article engages with an alternative form of nationalism found within the Nuuk underground...

  19. Semen quality in Greenland

    OpenAIRE

    Toft, Gunnar; Pedersen, Henning Sloth; Bonde, Jens Peter; research team, INUENDO

    2004-01-01

    Objectives. To quantify semen quality in the Greenlandic population. Study design. A cross-sectional study including recently proven fertile men from four regions including nine municipalities and one settlement in Greenland. Methods. The samples were analysed for sperm cell concentrations and motility using standard methods. Results. In total 201 semen samples were collected. The median sperm cell concentration of fertile men in Greenland was 53 x106 sperm cells/ml, with a median sperm cell ...

  20. Greenland and Natural Resources

    DEFF Research Database (Denmark)

    Lyck, Lise

    Greenland policy can delay and maybe change the future of the forecasted development of the use of natural resources. This book is relevant for anyone interested in Greenland in general and the development of Greenland both politically and economically and in relation natural resources.......The Greenland development is a story about: Having a hinterland position in relation to the global development. An indigenous people achieving more political influence. How conflicts and discussions on power and ownership of the subsurface resources between a state and an autonomy (Home Rule) can...

  1. Diachronous retreat of the Greenland ice sheet during the last deglaciation

    Science.gov (United States)

    Sinclair, G.; Carlson, A. E.; Mix, A. C.; Lecavalier, B. S.; Milne, G.; Mathias, A.; Buizert, C.; DeConto, R.

    2016-08-01

    The last deglaciation is the most recent interval of large-scale climate change that drove the Greenland ice sheet from continental shelf to within its present extent. Here, we use a database of 645 published 10Be ages from Greenland to document the spatial and temporal patterns of retreat of the Greenland ice sheet during the last deglaciation. Following initial retreat of its marine margins, most land-based deglaciation occurred in Greenland following the end of the Younger Dryas cold period (12.9-11.7 ka). However, deglaciation in east Greenland peaked significantly earlier (13.0-11.5 ka) than that in south Greenland (11.0-10 ka) or west Greenland (10.5-7.0 ka). The terrestrial deglaciation of east and south Greenland coincide with adjacent ocean warming. 14C ages and a recent ice-sheet model reconstruction do not capture this progression of terrestrial deglacial ages from east to west Greenland, showing deglaciation occurring later than observed in 10Be ages. This model-data misfit likely reflects the absence of realistic ice-ocean interactions. We suggest that oceanic changes may have played an important role in driving the spatial-temporal ice-retreat pattern evident in the 10Be data.

  2. Tracking intercumulus crystallisation at the Skaergaard intrusion using immobile trace elements: Evidence for liquid immiscibility

    Science.gov (United States)

    Humphreys, Madeleine

    2010-05-01

    A key target in the study of a layered intrusion is to constrain the liquid line of descent of the magma. However, the liquid line of descent of the intercumulus liquid is rarely considered, and is often assumed to be equivalent to that of the bulk magma. If the bulk liquid and interstitial liquids follow the same liquid line of descent, then intercumulus zoning profiles should be similar to the cryptic compositional variations seen with stratigraphic height. Because of extensive sub-solidus and diffusional changes that occur in slowly cooled rocks, clues to the composition of the intercumulus liquid can only be obtained using very slowly diffusing trace elements and components; the anorthite content of plagioclase and its Ti concentration are ideal in this respect. For the Skaergaard Intrusion, east Greenland, anorthite content (XAn) decreases monotonically as temperature decreases and the liquid becomes more evolved. The Ti content decreases in both cumulus and intercumulus plagioclase, as a result of falling liquid Ti after Fe-Ti oxides start to crystallise. However, Ti-XAn zoning in intercumulus plagioclase does not match the cryptic variations observed with increasing stratigraphic height, which demonstrates that the cumulus and intercumulus liquid lines of descent are not equivalent. In the intercumulus plagioclase, different trends develop adjacent to fine-grained, mafic and felsic interstitial pockets, which represent the crystallised products of trapped, late-stage immiscible liquids. The zoning trends vary systematically as a function of stratigraphic height and spatial location within the intrusion. The distribution and composition of the reversed plagioclase are used to infer the spatial distribution and differential movement of interstitial immiscible liquids throughout the Layered Series, and processes affecting the intercumulus liquid.

  3. Gravity-derived High-resolution Moho Model for Greenland

    Science.gov (United States)

    Steffen, R.; Strykowski, G.; Lund, B.

    2016-12-01

    Obtaining knowledge of the depth of the crust-mantle boundary (Mohorovičić discontinuity, Moho) beneath Greenland is important for the understanding of ice mass losses as those estimates depend on earth model parameters. However, the ice sheet on Greenland impedes the access and installation of seismological stations as well as the gathering of reflection and refraction seismic data, making the use of the most common methods to determine the crust-mantle boundary difficult. However, the Moho depth can be estimated also from gravity data through an inversion procedure and such data can, on the contrary, be obtained not only through ground measurements, but also through airborne campaigns as well as from satellite missions. Here, we use the Parker-Oldenburg algorithm together with the most recent EIGEN-6C4 gravity model to estimate the crust-mantle boundary beneath Greenland and surroundings. The available gravity data are corrected for the topographic effect, the gravity effect of sediments and the gravity effect of the ice load induced deformation. The resulting Moho model for Greenland shows maximum depths below east Greenland of up to 55 km and and values less than 20 km offshore east Greenland. The northern part of Greenland has a shallower Moho of only 30 km compared to southern Greenland, indicating a change in the crustal structures and the presence of two different crustal blocks in Greenland. An uncertainty of ±2.5 km is determined for the final model, which has a spatial resolution of 0.1°. The results of the gravity inversion are consistent with previous Moho models determined by seismological and seismic data mainly, where those are available. The comparison to previously estimated models based on older gravity data and using different inversion algorithms shows only small differences.

  4. West Greenlandic Eskimo

    DEFF Research Database (Denmark)

    Trondhjem, Naja Blytmann; Fortescue, Michael David

    the principal economic activity. Research projects and language initiatives currently in progress within Greenland will be touched upon, as will the possibilities of communication with North American Inuit. West Greenlandic is unique among the native languages of the North American Arctic and Sub...

  5. Health expectancy in Greenland

    DEFF Research Database (Denmark)

    Iburg, K M; Brønnum-Hansen, Henrik; Bjerregaard, P

    2001-01-01

    Mortality and disease patterns in Greenland have greatly changed since the 1950s. Infectious diseases have decreased markedly; chronic diseases, suicides and violent deaths have increased.......Mortality and disease patterns in Greenland have greatly changed since the 1950s. Infectious diseases have decreased markedly; chronic diseases, suicides and violent deaths have increased....

  6. Inuit health in Greenland

    DEFF Research Database (Denmark)

    Bjerregaard, P; Curtis, T; Borch-Johnsen, K

    2003-01-01

    During 1997-2001 a population survey was carried out amongst Greenland Inuit living in Denmark and West Greenland (Nuuk, Sisimiut, Qasigiannguit and four villages in Uummannaq municipality). Data collection comprised an interview, a questionnaire, clinical examinations and sampling of biological ...

  7. Studying health in Greenland

    DEFF Research Database (Denmark)

    Bjerregaard, Peter; Mulvad, Gert; Olsen, Jørn

    2003-01-01

    Health research in Greenland has contributed with several findings of interest for the global scientific community and has documented health problems and risk factors of importance for planning the local health care system. The study of how health develops in small, scattered communities during...... to that of the industrialized world, while still including local outbreaks of tuberculosis. Health research in Greenland is logistically difficult and costly, but offers opportunities not found elsewhere in the world. A long tradition of registration enhances the possibilities for research. A number of research institutions...... in Denmark and Greenland have conducted health research in Greenland for many years in cooperation with, among others, researchers in Canada and Alaska. National and international cooperation is supported by the Danish/Greenlandic Society for Circumpolar Health, the International Union for Circumpolar Health...

  8. Uncovering the genetic history of the present-day greenlandic population

    DEFF Research Database (Denmark)

    Moltke, Ida; Fumagalli, Matteo; Korneliussen, Thorfinn Sand;

    2015-01-01

    ∼200,000 SNPs from more than 10% of the adult Greenlandic population (n = 4,674). We found that recent gene flow from Europe has had a substantial impact on the population: more than 80% of the Greenlanders have some European ancestry (on average ∼25% of their genome). However, we also found...... between the Norse Vikings who lived in Greenland for a limited period ∼600-1,000 years ago and the Inuit, we found no evidence supporting this hypothesis. Similarly, we found no evidence supporting a previously hypothesized admixture event between the Inuit in East Greenland and the Dorset people, who...

  9. Interior intrusion detection systems

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, J.R.; Matter, J.C. (Sandia National Labs., Albuquerque, NM (United States)); Dry, B. (BE, Inc., Barnwell, SC (United States))

    1991-10-01

    The purpose of this NUREG is to present technical information that should be useful to NRC licensees in designing interior intrusion detection systems. Interior intrusion sensors are discussed according to their primary application: boundary-penetration detection, volumetric detection, and point protection. Information necessary for implementation of an effective interior intrusion detection system is presented, including principles of operation, performance characteristics and guidelines for design, procurement, installation, testing, and maintenance. A glossary of sensor data terms is included. 36 figs., 6 tabs.

  10. Interior intrusion detection systems

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, J.R.; Matter, J.C. (Sandia National Labs., Albuquerque, NM (United States)); Dry, B. (BE, Inc., Barnwell, SC (United States))

    1991-10-01

    The purpose of this NUREG is to present technical information that should be useful to NRC licensees in designing interior intrusion detection systems. Interior intrusion sensors are discussed according to their primary application: boundary-penetration detection, volumetric detection, and point protection. Information necessary for implementation of an effective interior intrusion detection system is presented, including principles of operation, performance characteristics and guidelines for design, procurement, installation, testing, and maintenance. A glossary of sensor data terms is included. 36 figs., 6 tabs.

  11. Excess water generation during reaction-inducing intrusion of granitic melts into ultramafic rocks at crustal P-T conditions in the Sør Rondane Mountains of East Antarctica

    Science.gov (United States)

    Uno, Masaoki; Okamoto, Atsushi; Tsuchiya, Noriyoshi

    2017-07-01

    Arc magmas are one of the main sources of aqueous geofluids in the crust, and the movement of fluids above magma chambers has been geophysically imaged. Here, we constrain the water budget (i.e., supply, consumption and release of H2O) in these areas above magma chamber by examining the hydration caused by crust-melt reactions in the Sør Rondane Mountains of East Antarctica. The study area contains a phlogopite-pargasite-peridotite unit that has been intruded by numerous granitic dikes, creating hydration reaction zones at the dike-peridotite boundary. These reactions occurred at 0.5 GPa and 700 °C, corresponding to middle crustal conditions, and generated a series of reaction zones with distance from the granitic dikes as follows: (i) granitic dike, (ii) pargasite-actinolite zone, (iii) tremolite-phlogopite zone, (iv) anthophyllite-phlogopite zone, (v) phlogopite-olivine-orthopyroxene zone, and (vi) unaltered pargasite-phlogopite peridotite. The presence of amphiboles with a preferred orientation perpendicular to the dike margins and an absence of Cr-rich magnetite indicate that the pargasite-actinolite zone [zone (ii)] grew from the dike margins as a result of the dike reacting with the host rock, with an initial melt/rock boundary located between zones (ii) and (iii). The H2O contents of reaction zones (ii)-(v) are higher than the content in the hosting pargasite-phlogopite peridotite, suggesting that the intrusion of the dike was associated with hydration reactions. Geochemical analysis along a profile through the reaction zones indicates Mg and Fe depletion, and Si enrichment in zones (iii)-(iv), and Ca depletion and K enrichment in zones (iv)-(v) relative to the hosting pargasite-phlogopite peridotite. In contrast, zone (ii) is characterized by Ca, Fe, and Mg enrichments relative to the granitic dike. These observations suggest that the reaction zone sequence was formed by the elemental transfer between granitic dike and parasite-phlogopite peridotite: Ca

  12. Distribution and drift of Atlantic cod ( Gadus morhua ) eggs and larvae in Greenland offshore waters

    DEFF Research Database (Denmark)

    Wieland, Kai; Hovgård, Holger

    2002-01-01

    Catches of Atlantic cod (Gadus morhua) eggs and larvae from 45 national and international ichthyoplankton surveys conducted in Greenland offshore waters during the period 1950 to 1984 have been compiled and re-analysed. Southeast and Southwest Greenland were identified as im- portant spawning areas...... from which eggs and early larvae drift towards the southern Davis Strait. Only a part of the larval population remained in the vicinity of favourable settling areas off West Greenland while a considerable part was obviously transported westward across the Davis Strait and thus did not contribute...... to the recruitment of the West Greenland cod stock. It is also shown that cod eggs and larvae occasionally drift from Southwest Iceland across the Denmark Strait to the East Greenland shelf from where a subsequent transport and immigration of juveniles to West Greenland waters can occur. Larval transport across...

  13. Uncovering the genetic history of the present-day greenlandic population

    DEFF Research Database (Denmark)

    Moltke, Ida; Fumagalli, Matteo; Korneliussen, Thorfinn Sand

    2015-01-01

    Because of past limitations in samples and genotyping technologies, important questions about the history of the present-day Greenlandic population remain unanswered. In an effort to answer these questions and in general investigate the genetic history of the Greenlandic population, we analyzed...... ∼200,000 SNPs from more than 10% of the adult Greenlandic population (n = 4,674). We found that recent gene flow from Europe has had a substantial impact on the population: more than 80% of the Greenlanders have some European ancestry (on average ∼25% of their genome). However, we also found...... that the amount of recent European gene flow varies across Greenland and is far smaller in the more historically isolated areas in the north and east and in the small villages in the south. Furthermore, we found that there is substantial population structure in the Inuit genetic component of the Greenlanders...

  14. Seismic structure of the crust and upper mantle in central-eastern Greenland

    DEFF Research Database (Denmark)

    Kraft, Helene Anja

    at the east coast to 50 km in central Greenland. The observed crustal thicknesses indicate that the high topography in eastern Greenland of up to 3700 m cannot be explained by Airy type isostatic equilibrium alone. Major parts of the mantle transition zone below central-eastern Greenland are substantially......Geophysical and geological knowledge of the interior of Greenland is very limited. The lack of knowledge arises mainly due to the logistical challenges related to conducting geophysical fieldwork on the up to 3400 m thick ice sheet, which covers around 80% of the land area. This PhD thesis is based...... on the very first regional passive seismic study in central-Eastern Greenland, focusing on the area between Scoresby Sund and Summit. The study aims to image the structure of subsurface Greenland starting from the crust and down to the mantle transition zone. Furthermore, the thesis links these observations...

  15. Important role of magma mixing in generating the Mesozoic monzodioritic-granodioritic intrusions related to Cu mineralization, Tongling, East China: evidence from petrological and in situ Sr-Hf isotopic data

    Science.gov (United States)

    Chen, Bin; Chen, ChangJian

    2016-04-01

    The Mesozoic ore-bearing high-Mg monzodioritic-granodioritic rocks in the Tongling mining district (East China) have been described as having adakitic affinities, and their origin has been attributed to partial melting of delaminated eclogite at depth in the mantle, followed by interaction of the resultant granitic magma with mantle peridotite. Here we present petrological data and in situ Sr isotopic data for zoned plagioclase that are inconsistent with the eclogite-derived model, and instead propose a model that involves magma mixing of siliceous crustal melts and basaltic magma that was derived from metasomatized mantle by subduction zone fluids in an extensional regime. The principal geochemical signatures of these Mesozoic rocks include a hydrous and high-K calc-alkaline affinity, high values of Mg#, high Sr abundances, high Sr/Y and La/Yb ratios, ɛNd(t)=-13.1 to -9.0, and ISr=0.70707-0.70824. The magma mixing model is supported by (1) the common existence of mafic microgranular enclaves (MMEs) and the disequilibrium textures of plagioclase and hornblende, (2) the increase in Ti and Al(IV) from hornblende cores to rims, and the overgrowths of high-Ca pyroxene around hornblende grains as well, indicative of episode of heating and rejuvenation of the magma chamber as a result of recharge of mafic magma, (3) the 87Sr/86Sr ratios of embayed high-Ca cores of plagioclase that are distinctly lower than in the euhedral low-Ca overgrowth rims, (4) negative correlations between whole-rock Nd and Sr isotopic ratios, and (5) the significant differences in the values of ɛHf(t) (-9.5 to -26) within different zircons from the same intrusion. We propose that underplating of hydrous basaltic magma from the metasomatized lithospheric mantle in the lower crust resulted in partial melting of the lower crustal rocks (Precambrian TTG gneisses and amphibolite/granulite) under water-saturated conditions, during which plagioclase decomposed, leaving hornblende-rich restites and

  16. Isotopes in Greenland Precipitation

    DEFF Research Database (Denmark)

    Faber, Anne-Katrine

    the Arctic Ocean. A comprehensive database is created based on ice core and weather station data from Greenland within the period 1890-2014. Present day annual and seasonal mean values are computed for 326 locations in Greenland. Parameterization of the spatial distribution of temperature and δ18O are used...... of model and data can be used to improve the understanding of climate changes. This is done through analysis of isotope modelling, observations and ice core measurements. This dissertation comprises three projects: (1) Modelling the isotopic response to changes in Arctic sea surface conditions, (2......) Constructing a new Greenland database of observations and present-day ice core measurements, and (3) Performance test of isotope-enabled CAM5 for Greenland. The recent decades of rapid Arctic sea ice decline are used as a basis for an observational-based model experiment using the isotope-enabled CAM model 3...

  17. Child health in Greenland

    DEFF Research Database (Denmark)

    Niclasen, Birgit V L; Bjerregaard, Peter

    2007-01-01

    importance to the health of children in Greenland. More accurate data on child health are necessary in the future to secure better prioritization. It is suggested to construct a set of reliable indicators of child health in Greenland to monitor the health of children on a national and regional basis....... were sorted by topic, type, quality of study, and relevance for child health today, providing 47 articles. RESULTS: Children in Greenland have become taller and have improved their general health. The morbidity found in Greenlandic children is similar to that found elsewhere even though the magnitude....... Overweight and obesity have tripled in 20 years and are a health threat as well as constituting negative health behaviour. Social ill health, socioeconomic inequity, and sociocultural changes also influence health but their consequences are not well investigated in children. CONCLUSIONS: A relatively high...

  18. Isotopes in Greenland Precipitation

    DEFF Research Database (Denmark)

    Faber, Anne-Katrine

    Greenland ice cores offer a unique opportunity to investigate the climate system behaviour. The objective of this PhD project is to investigate isotope modelling of present- day conditions and conduct model-data comparison using Greenland ice cores. Thus this thesis investigates how the integration...... of model and data can be used to improve the understanding of climate changes. This is done through analysis of isotope modelling, observations and ice core measurements. This dissertation comprises three projects: (1) Modelling the isotopic response to changes in Arctic sea surface conditions, (2......) Constructing a new Greenland database of observations and present-day ice core measurements, and (3) Performance test of isotope-enabled CAM5 for Greenland. The recent decades of rapid Arctic sea ice decline are used as a basis for an observational-based model experiment using the isotope-enabled CAM model 3...

  19. Telemedicine in Greenland

    DEFF Research Database (Denmark)

    Nielsen, Lasse Overballe; Krebs, Hans Jørgen; Albert, Nancy M.

    2017-01-01

    . Regarding challenges in using telemedicine in Greenland, the geographical and cultural context hinders accessibility to the Greenlandic healthcare system, and telemedicine equipment is not sufficiently mobile. CONCLUSION: Greenlandic citizens are positive toward telemedicine and regard telemedicine......BACKGROUND: Telemedicine may have the possibility to provide better access to healthcare delivery for the citizens. Telemedicine in arctic remote areas must be tailored according to the needs of the local population. Therefore, we need more knowledge about their needs and their view of telemedicine....... OBJECTIVE: The aim of this study has been to explore how citizens living in the Greenlandic settlements experience the possibilities and challenges of telemedicine when receiving healthcare delivery in everyday life. MATERIALS AND METHODS: Case study design was chosen as the overall research design...

  20. Greenland climate change

    DEFF Research Database (Denmark)

    Masson-Delmotte, Valerie; Swingedouw, D.; Landais, A.

    2012-01-01

    Climate archives available from deep-sea and marine shelf sediments, glaciers, lakes and ice cores in and around Greenland allow us to place the current trends in regional climate, ice sheet dynamics, and land surface changes in a broader perspective. We show that during the last decade (2000s...... regional climate and ice sheet dynamics. The magnitude and rate of future changes in Greenland temperature, in response to increasing greenhouse gas emissions, may be faster than any past abrupt events occurring under interglacial conditions. Projections indicate that within one century Greenland may......), atmospheric and sea-surface temperatures are reaching levels last encountered millennia ago when northern high latitude summer insolation was higher due to a different orbital configuration. Concurrently, records from lake sediments in southern Greenland document major environmental and climatic conditions...

  1. Q fever in Greenland

    DEFF Research Database (Denmark)

    Koch, Anders; Svendsen, Claus Bo; Christensen, Jens Jorgen

    2010-01-01

    We report a patient with Q fever endocarditis in a settlement in eastern Greenland (Isortoq, Ammassalik area). Likely animal sources include sled dogs and seals. Q fever may be underdiagnosed in Arctic areas but may also represent an emerging infection.......We report a patient with Q fever endocarditis in a settlement in eastern Greenland (Isortoq, Ammassalik area). Likely animal sources include sled dogs and seals. Q fever may be underdiagnosed in Arctic areas but may also represent an emerging infection....

  2. The Greenland shark

    DEFF Research Database (Denmark)

    Costantini, David; Smith, Shona; Killen, Shaun S.;

    2017-01-01

    the oxidative status of the Greenland shark (Somniosus microcephalus), which has recently been found as the longest living vertebrate animal known to science with a lifespan of at least 272years. As compared to other species, the Greenland shark had body mass-corrected values of muscle glutathione peroxidase...... that the values of metrics of oxidative status we measured might be linked to ecological features (e.g., adaptation to cold waters and deep dives) of this shark species rather to its lifespan....

  3. Q fever in Greenland

    DEFF Research Database (Denmark)

    Koch, Anders; Svendsen, Claus Bo; Christensen, Jens Jorgen

    2010-01-01

    We report a patient with Q fever endocarditis in a settlement in eastern Greenland (Isortoq, Ammassalik area). Likely animal sources include sled dogs and seals. Q fever may be underdiagnosed in Arctic areas but may also represent an emerging infection.......We report a patient with Q fever endocarditis in a settlement in eastern Greenland (Isortoq, Ammassalik area). Likely animal sources include sled dogs and seals. Q fever may be underdiagnosed in Arctic areas but may also represent an emerging infection....

  4. The Greenland Ramsar Sites

    DEFF Research Database (Denmark)

    Egevang, C.; Boertmann, D.

    The eleven Ramsar sites in Greenland are reviewed in terms of their status as habitats for waterbirds and other fauna. Management and monitoring is proposed, as well as revisions of their boundaries. A number of potential new Ramsar sites are described......The eleven Ramsar sites in Greenland are reviewed in terms of their status as habitats for waterbirds and other fauna. Management and monitoring is proposed, as well as revisions of their boundaries. A number of potential new Ramsar sites are described...

  5. Walruses in West Greenland: Where do they belong?

    DEFF Research Database (Denmark)

    Born, E. W.; Andersen, L. W.; Dietz, R.

    identity of walruses in CWG remains undetermined. Genetic studies indicate that CWG-walruses have only little exchange with walruses in Northwest and East Greenland. However, a comparison between walruses from Hudson Strait (HS) in Canada) and CWG indicated a source (HS)-sink (CWG) relationship between...

  6. Radioisotope-excited x-ray fluorescence analysis and its application to geochemical exploration in Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Kunzendorf, H.

    1973-05-01

    dealt with. Special emphasis is given to the correction of x-ray intensities by means of scattered x-radiation. Portable radioisotope x-ray fluorescence analyzers were applied in geochemical investigations of Zr, Nb, and La + Ce in a series of alkaline rocks of the Ilimaussaq intrusion, South Greenland, of Mo in molybdenitebearing rocks, and of Zr and La + Ce in sedimentry rocks from East Greenland. Semiconductor x-ray spectrometers were used in the analysis of sediments from a stream draining the Ilimaussaq intrusion, South Greenland, in the analysis of La, Ce, Ni, Cu, and Zn in stream sediments from East Greenland, and in investigations of Rb, Sr, Zr, Nb, Sn, Ha, La, Ce, Pr, and Nd in cut drill cores. ( auth)

  7. Ice age plant refugia in East Greenland

    DEFF Research Database (Denmark)

    Funder, Svend Visby

    1979-01-01

    evidence it is inferred that the flora in the refugia comprised mainly species which today occur over a wide geographical and ecological range. The "odd" occurrences that initiated the discussion may represent random.seed dispersal accumulated in the ice-free areas through long periods of time...

  8. Age of Tertiary volcanic rocks on the West Greenland continental margin

    DEFF Research Database (Denmark)

    Larsen, Lotte M.; Pedersen, Asger K.; Tegner, Christian

    2016-01-01

    Radiometric ages for undated parts of the volcanic succession and intrusions in West Greenland were obtained by the 40Ar–39Ar incremental heating method. Acceptable crystallization ages were obtained for 27 samples. Combined with published results the new data provide a volcanic stratigraphy corr...

  9. First Younger Dryas moraines in Greenland

    Science.gov (United States)

    Funder, Svend; Larsen, Nicolaj K.; Linge, Henriette; Möller, Per; Schomacker, Anders; Fabel, Derek; Kjær, Kurt H.; Xu, Sheng

    2016-04-01

    Over the Greenland ice sheet the Younger Dryas (YD) cold climate oscillation (12.9-11.7 kaBP) began with up to 10°C drop in temperatures and ended with up to 12°C abrupt warming. In the light of the present warming and melting of the ice sheet, and its importance for future climate change, the ice sheet's response to these dramatic changes in the past is of great interest. However, even though much effort has gone into charting YD ice margin behaviour around Greenland in recent years, no clear-cut signal of response to the oscillation has been uncovered. Here we show evidence to suggest that three major outlets from a local ice cap at Greenland's north coast advanced and retreated synchronously during YD. The evidence comprises OSL (optically stimulated luminescence) dates from a marine transgression of the coastal valleys that preceded the advance, and exposure ages from boulders on the moraines, formed by glaciers that overrode the marine sediment. The OSL ages suggest a maximum age of 12.4 ±0.6 kaBP for the marine incursion, and 10 exposure ages on boulders from the three moraines provide an average minimum age of 12.5 ±0.7 kaBP for the moraines, implying that the moraines were formed within the interval 11.8-13.0 kaBP. Elsewhere in Greenland evidence for readvance has been recorded in two areas. Most notably, in the East Greenland fjord zone outlet glaciers over a stretch of 800 km coast advanced through the fjords. In Scoresby Sund, where the moraines form a wide belt, an extensive 14C and exposure dating programme has shown that the readvance here probably culminated before YD, while cessation of moraine formation and rapid retreat from the moraine belt did not commence until c. 11.5 kaBP, but no moraines have so far been dated to YD. Readvance is also seen in Disko Bugt, the largest ice sheet outlet in West Greenland. However, here the advance and retreat of the ice stream took place in mid YD times, and lasted only a few hundred years, while YD in

  10. Immiscible iron- and silica-rich melts in basalt petrogenesis documented in the Skaergaard intrusion

    Science.gov (United States)

    Jakobsen, J. K.; Veksler, I. V.; Tegner, C.; Brooks, C. K.

    2005-11-01

    Silicate liquid immiscibility in basalt petrogenesis is a contentious issue. Immiscible iron- and silica-rich liquids were reported in melt inclusions of lunar basalt and in groundmass glasses of terrestrial volcanics. In fully crystallized plutonic rocks, however, silicate liquid immiscibility has yet to be proven. Here we report the first finding of natural, immiscible iron- and silica-rich melts in a plutonic environment documented in the Skaergaard intrusion, East Greenland. Primary melt inclusions (now finely crystallized) in apatite are either dark or light colored. The predominant dark colored type contains 30.9 ± 4.2 wt% FeOt and 40.7 ± 3.6 wt% SiO2, whereas the light colored type contains 8.6 ± 5.9 wt% FeOt and 65.6 ± 7.3 wt% SiO2. Similar light colored melt inclusions in olivine and fine-grained dark and light colored interstitial pockets also give evidence of crystallization from emulsion of silica and iron-rich liquids. On the outcrop scale, silica-rich (melanogranophyre) pods and layers in iron-rich ferrodiorite of the Upper Zone of the Skaergaard intrusion witness segregation of the two liquids. These findings demand that silicate immiscibility is considered in basalt petrogenesis. Some granitic rocks may represent unmixed silica-rich melt, whereas the dense, iron-rich melt is likely to sink in the crust and could mix with hot mantle-derived magma to form unusual rocks, like ferropicrites, otherwise interpreted as products of heterogeneous mantle sources.

  11. Computer Intrusions and Attacks.

    Science.gov (United States)

    Falk, Howard

    1999-01-01

    Examines some frequently encountered unsolicited computer intrusions, including computer viruses, worms, Java applications, trojan horses or vandals, e-mail spamming, hoaxes, and cookies. Also discusses virus-protection software, both for networks and for individual users. (LRW)

  12. Uncovering the genetic history of the present-day Greenlandic population.

    Science.gov (United States)

    Moltke, Ida; Fumagalli, Matteo; Korneliussen, Thorfinn S; Crawford, Jacob E; Bjerregaard, Peter; Jørgensen, Marit E; Grarup, Niels; Gulløv, Hans Christian; Linneberg, Allan; Pedersen, Oluf; Hansen, Torben; Nielsen, Rasmus; Albrechtsen, Anders

    2015-01-01

    Because of past limitations in samples and genotyping technologies, important questions about the history of the present-day Greenlandic population remain unanswered. In an effort to answer these questions and in general investigate the genetic history of the Greenlandic population, we analyzed ∼200,000 SNPs from more than 10% of the adult Greenlandic population (n = 4,674). We found that recent gene flow from Europe has had a substantial impact on the population: more than 80% of the Greenlanders have some European ancestry (on average ∼25% of their genome). However, we also found that the amount of recent European gene flow varies across Greenland and is far smaller in the more historically isolated areas in the north and east and in the small villages in the south. Furthermore, we found that there is substantial population structure in the Inuit genetic component of the Greenlanders and that individuals from the east, west, and north can be distinguished from each other. Moreover, the genetic differences in the Inuit ancestry are consistent with a single colonization wave of the island from north to west to south to east. Although it has been speculated that there has been historical admixture between the Norse Vikings who lived in Greenland for a limited period ∼600-1,000 years ago and the Inuit, we found no evidence supporting this hypothesis. Similarly, we found no evidence supporting a previously hypothesized admixture event between the Inuit in East Greenland and the Dorset people, who lived in Greenland before the Inuit.

  13. Distance learning in the arctic wilderness of northeast Greenland

    DEFF Research Database (Denmark)

    Langebæk, Rikke

    2011-01-01

    ABSTRACT In North East Greenland, the Danish Sirius Sledge Patrol conducts long-range patrolling in pairs of two soldiers and a team of sled dogs. Trips last 4 months or more and soldiers have no outside human contact. Each year seven new soldiers are selected to undergo seven months training....../distance learning as an addition to the practical course. Thus, extensive video-filming was done on location in Greenland, illustrating a range of different situations related to handling, examining and treating the sled dogs. The narrated videos now constitute the new mobile teaching material that was implemented...

  14. How Greenland melts

    Directory of Open Access Journals (Sweden)

    van den Broeke M.R.

    2010-12-01

    Full Text Available Satellite altimetry and gravimetry show that the Greenland ice sheet has been losing volume and mass since the beginning of this century. However, from these short time series of direct measurements we cannot infer what the causes of the mass loss are, i.e. ice dynamics or surface processes, or that maybe the ice sheet returns to normal after a period of volume increase and mass gain. By modelling and observing the individual components of the ice sheet mass balance, i.e. snowfall, meltwater runoff and iceberg production, we are able to identify the processes that led to the recent mass loss. We conclude that the Greenland ice sheet is significantly out of balance. Acceleration of outlet glaciers and increased runoff have contributed equally to recent Greenland mass loss. The potential for mass loss by surface processes, however, was three times greater than actually observed, due to refreezing and enhanced snowfall.

  15. CNS infections in Greenland

    DEFF Research Database (Denmark)

    Nordholm, Anne Christine; Søborg, Bolette; Andersson, Mikael

    2017-01-01

    BACKGROUND: Indigenous Arctic people suffer from high rates of infectious diseases. However, the burden of central nervous system (CNS) infections is poorly documented. This study aimed to estimate incidence rates and mortality of CNS infections among Inuits and non-Inuits in Greenland...... and in Denmark. METHODS: We conducted a nationwide cohort study using the populations of Greenland and Denmark 1990-2012. Information on CNS infection hospitalizations and pathogens was retrieved from national registries and laboratories. Incidence rates were estimated as cases per 100,000 person......-years. Incidence rate ratios were calculated using log-linear Poisson-regression. Mortality was estimated using Kaplan-Meier curves and Log Rank test. RESULTS: The incidence rate of CNS infections was twice as high in Greenland (35.6 per 100,000 person years) as in Denmark (17.7 per 100,000 person years...

  16. China and Greenland

    DEFF Research Database (Denmark)

    Jakobsen, Uffe

    2014-01-01

    More thorough analysis and outreach on facts about Chinese activities in the Arctic are highly needed, not least in view of the almost alarmist response in Danish political debate to the prospects of growing Chinese interest in the Arctic in general and especially in Greenland......More thorough analysis and outreach on facts about Chinese activities in the Arctic are highly needed, not least in view of the almost alarmist response in Danish political debate to the prospects of growing Chinese interest in the Arctic in general and especially in Greenland...

  17. Network intrusion detection

    Institute of Scientific and Technical Information of China (English)

    Oboile Tirelo; YANG Chun-hua

    2003-01-01

    Nowadays, network computer systems play an increasingly important role in society and economy. They have become the targets of a wide array of malicious attacks that invariably turn into actual intrusions. This is why the computer security has become an essential concern for network administrators. Too often, intrusions wreak havoc inside LANs and the time and cost to repair the damage can grow to extreme proportions. Instead of using passive measures to fix and patch security holes once they have been exploited, it is more effective to adopt a protective approach to intrusions. In addition to the well-established intrusion prevention techniques such as data encryption and message integrity, user authentication and user authorization, as well as the avoidance of security flaws inherent to many off-the-shelf applications, intrusion detection techniques can be viewed as an addition safeguard for network computers. The paper discusses traditional and new security designs, the approach to implementing best-practice security measures and the method to trace the malicious computer attackers.

  18. The Greenland Ramsar Sites

    DEFF Research Database (Denmark)

    Egevang, C.; Boertmann, D.

    The eleven Ramsar sites in Greenland are reviewed in terms of their status as habitats for waterbirds and other fauna. Management and monitoring is proposed, as well as revisions of their boundaries. A number of potential new Ramsar sites are described...

  19. China and Greenland

    DEFF Research Database (Denmark)

    Jakobsen, Uffe

    2014-01-01

    More thorough analysis and outreach on facts about Chinese activities in the Arctic are highly needed, not least in view of the almost alarmist response in Danish political debate to the prospects of growing Chinese interest in the Arctic in general and especially in Greenland...

  20. How Greenland melts

    NARCIS (Netherlands)

    van den Broeke, M.R.

    2010-01-01

    Satellite altimetry and gravimetry show that the Greenland ice sheet has been losing volume and mass since the beginning of this century. However, from these short time series of direct measurements we cannot infer what the causes of the mass loss are, i.e. ice dynamics or surface processes, or that

  1. How Greenland melts

    NARCIS (Netherlands)

    van den Broeke, M.R.

    2010-01-01

    Satellite altimetry and gravimetry show that the Greenland ice sheet has been losing volume and mass since the beginning of this century. However, from these short time series of direct measurements we cannot infer what the causes of the mass loss are, i.e. ice dynamics or surface processes, or that

  2. Commentary: Future Greenland 2015

    DEFF Research Database (Denmark)

    Bjørst, Lill Rastad

    2015-01-01

    Every second year the Greenlandic Business Association host the two-day conference “Future Greenland” in Nuuk. The main theme of this year conference was “Growth and welfare – scenarios for the development of Greenland”. The conference had more than 400 participants - mostly from Denmark and Gree...

  3. Inuit health in Greenland

    DEFF Research Database (Denmark)

    Bjerregaard, P; Curtis, T; Borch-Johnsen, K

    2003-01-01

    specimens (blood, urine, subcutaneous fat tissue). The clinical examinations included anthropometric measurements, an oral glucose tolerance test, ECG, ultrasound of thyroid gland and carotid arteries, a skin prick test, and lung function. The data collection areas in Greenland ranged from the westernized...

  4. APISSEQ Sisimiut – Greenland

    DEFF Research Database (Denmark)

    Kotol, Martin

    This report summarizes the very first survey of the engineering dormitory Apisseq in Sisimiut, Greenland. The dormitory was inaugurated in August 2010 and the survey was performed in March 2011. The experienced problems and their possible causes are explained in the report. Furthermore possible...

  5. Research on the dry intrusion accompanying the low vortex precipitation

    Institute of Scientific and Technical Information of China (English)

    YAO; XiuPing; WU; GuoXiong; ZHAO; BingKe; YU; YuBin; YANG; GuiMing

    2007-01-01

    By employing the 6.7μm satellite vapor cloud images and NCEP/NCAR 1°×1° reanalysis datasets, the characteristics and mechanism of the dry intrusion, as well as its impacts on the low vortex precipitation at the Meiyu front are explored in this paper. It is found that the formation,development and maintenance of the low vortex precipitation at the Meiyu front are closely related to the evolution of the dry intrusion. The dry intrusion is characterized by high potential vorticity (PV), low humidity and cold air. The dry intrusion exhibits as an obvious dark zone on vapor cloud images, an area in which atmospheric relative humidity is lower than 60%. However, the features of the dry intrusion on the vapor images are clearer than that of the humidity field, for the former is the digital vapor cloud images with high temporal and spatial resolution, and it can be used to explore the finer characteristics of the development, evolution and supplement of the intrusion during the development of the low vortex. The dry intrusion impacts accompanying the low vortex precipitation at the Meiyu front come from all levels of the troposphere, with the strongest intrusion located at the upper troposphere. The dry and cold air intrudes the vicinity of the low vortex from the upper isentropic surface to the lower one, slanting east-ward from lower to higher level. The low vortex precipitation region is usually situated in front of the dry intrusion where the relative humidity gradient is higher. The research also reveals that the mechanism of the dry intrusion is that the high potential vorticity descends from the upper troposphere to the lower level, therefore, the dry intrusion can be used as an important index of the high PV forcing. To the west of the low vortex precipitation, the upper level northerlies descend across the isentropic surface, then the dry cold advection can trigger the instable development in the midlow troposphere. The dry intru-sion enhances the low vortex

  6. Network Intrusion Dataset Assessment

    Science.gov (United States)

    2013-03-01

    Science, pages 576–585. Springer Berlin / Heidelberg, June 2010. • Jing Xiao-Pei and Wang Hou -Xiang. “A new immunity intrusion detection model based on...2008. • Hongying Zheng, Meiju Hou , and Yu Wang. “An efficient hybrid clustering-PSO algorithm for anomaly intrusion detection.” Journal of Software...Technology, 2(6):1790– 1799, 2010. [34] Lee, Suchul, Hyunchul Kim, Dhiman Barman, Sungryoul Lee, Chong -kwon Kim, Ted Kwon, and Yanghee Choi. “NeTraMark: a

  7. A new glacier monitoring site in West Greenland

    Science.gov (United States)

    Abermann, J.; van As, D.; Petersen, D.; Nauta, M.

    2014-12-01

    Greenland's mountain glaciers and ice caps have recently been shown to significantly contribute to current and future sea-level rise. Despite their importance in this respect they are heavily undersampled with only about 5 currently monitored glaciers out of more than 20000 distributed over complexly varying climatic regions. In 2012, Asiaq, Greenland Survey initiated therefore a glacier mass balance program at Qassinnguit glacier (64°9'N, 51°17'W), approx. 18 km East of Nuuk, Greenland's capital. The glacier is a representative example for mountain glaciers in South-West Greenland both in terms of size (ca 1 km2) and orientation (N). A dense stake network gives the basis for the determination of the surface mass balance with the glaciological method as well as flow velocity measurements and the first two complete years are presented. An automated camera is used to monitor ablation patterns and the evolution of the snow line. In early 2014, a ground-penetrating radar campaign was performed to determine the glacier volume. Ice thicknesses up to 50 m were measured with a 100 MHz antenna and the glacier was found to be largely cold-based with some minor temperate parts. In addition to direct glaciological measurements at the site, the monitoring program complements a 7 year long time series of runoff, which allows for quantifying Qassinnguit glacier's cryospheric contribution to the total catchment. In summer 2014 an on-glacier automated weather station was installed that measures parameters to determine the surface energy balance. Preliminary results will be presented and put into a larger spatial context by relating them to measurements with the same setup at an outlet glacier of the Greenland ice sheet approximately 100 km further East. Climate between these sites differs considerably with a marked negative West - East precipitation gradient.

  8. Bourdieu in Greenland

    DEFF Research Database (Denmark)

    Hussain, Naimah

    2017-01-01

    with a small elite and close ties between reporters and possible sources shape the field practically, professionally and socially (in a specific, local way). These tensions between the “global-colonial” and “local” capitals and capacities are negotiated and managed in the everyday practices of newsrooms......, structured space. At the same time, however, the “post-colonial” realities of Greenlandic journalism can help us to pose some questions about the limits – or the need for further development – of Bourdieu’s initial sketch about the journalistic field. This chapter tests the analytical concepts of capital......The scarcely populated island of Greenland offers a unique opportunity both to study the complex dependencies and tensions of contemporary “global” or “transnational” journalism and to test and develop the explanation power of one key theoretical framework, field theory. With only one (national...

  9. Wastewater Treatment in Greenland

    DEFF Research Database (Denmark)

    Gunnarsdottir, Ragnhildur

    The Arctic nature is vulnerable to environmental contaminants because of low biological diversity, lack of nutrients and extreme seasonal variations in light. In Greenland neither industrial nor domestic wastewater is treated before it is discharged to the recipients, which in most cases is the sea...... treatment in these regions. However, designing, constructing and operating wastewater collection systems in the Arctic is challenging because of e.g. permafrost conditions, hard rock surfaces, freezing, limited quantity of water and high costs of electricity, fuel and transportation, as well as a settlement...... collection systems, and be more economically and environmentally sustainable than traditional wastewater collection and treatment systems. Possible alternative wastewater treatment methods for Greenlandic communities are dry composting or anaerobic digestion of excreta, collected at household level using dry...

  10. Preliminary screening of perfluorooctane sulfonate (PFOS) and other fluorochemicals in fish, birds and marine mammals from Greenland and the Faroe Islands

    Energy Technology Data Exchange (ETDEWEB)

    Bossi, Rossana [National Environmental Research Institute, Frederiksborgvej 399, 4000-Roskilde (Denmark)]. E-mail: rbo@dmu.dk; Riget, Frank F. [National Environmental Research Institute, Frederiksborgvej 399, 4000-Roskilde (Denmark); Dietz, Rune [National Environmental Research Institute, Frederiksborgvej 399, 4000-Roskilde (Denmark); Sonne, Christian [National Environmental Research Institute, Frederiksborgvej 399, 4000-Roskilde (Denmark); Fauser, Patrik [National Environmental Research Institute, Frederiksborgvej 399, 4000-Roskilde (Denmark); Dam, Maria [Food and Environmental Agency, Thorshavn, Faroe Islands (Denmark); Vorkamp, Katrin [National Environmental Research Institute, Frederiksborgvej 399, 4000-Roskilde (Denmark)

    2005-07-15

    Extensive screening analyses of perfluorooctane sulfonate (PFOS) and related perfluorinated compounds in biota samples from all over the world have identified PFOS as a global pollutant and have shown its bioaccumulation into higher trophic levels in the food chain. Perfluorinated compounds have been found in remote areas as the Arctic. In this study a preliminary screening of PFOS and related compounds has been performed in liver samples of fish, birds and marine mammals from Greenland and the Faroe Islands. PFOS was the predominant fluorochemical in the biota analyzed, followed by perfluorooctane sulfonamide (PFOSA). PFOS was found at concentrations above LOQ (10 ng/g wet weight) in 13 out of 16 samples from Greenland and in all samples from the Faroe Islands. The results from Greenland showed a biomagnification of PFOS along the marine food chain (shorthorn sculpineast Greenland (mean: 1285 ng/g wet weight, n=2). The geographical distribution of perfluorinated compounds in Greenland was similar to that of persistent organohalogenated compounds (OHCs), with the highest concentrations in east Greenland, indicating a similar geographical distribution to that of OHCs, with higher concentrations in east Greenland than in west Greenland. - Perfluorinated acids were detected in livers of fish, birds and marine mammals from Greenland and the Faroe Islands.

  11. Liquids of the Skaergaard intrusion traced by melt inclusions

    Science.gov (United States)

    Jakobsen, J. K.; Veksler, I. V.; Tegner, C.

    2009-12-01

    The Skaergaard intrusion, East Greenland, has for the past 75 years played a central role in the understanding of differentiation of tholeiitic magma. However, there is still no agreement on the general line of liquid descent. Here we compile the inference from melt inclusion in cumulus apatite and plagioclase as a direct tracer of the parental melt composition and its evolution. Compositions of crystallized melt inclusions have been estimated by broad beam analysis, mass balance summation and by remelting and homogenization. Melt inclusions in apatite are found in the Upper Zone and are of two types: One is dark brownish or opaque and contains finely crystallized daughter phases of plagioclase, ilmenite, magnetite, iron-rich biotite (lepidomelane) and a fine-grained matrix; a less abundant type is light-colored, transparent and consists of quartz, orthoclase, albite, minor magnetite and finely intergrown matrix. The predominant dark melt inclusions are extremely rich in FeOT (30.9 ± 4.2 wt%) and low in SiO2 (40.7 ± 3.6 wt%) whereas the light colored type contains 8.6 ± 5.9 wt% FeOT and 65.6 ± 7.3 wt% SiO2. The contrasting compositions is interpreted as entrapment of conjugate end-members of two immiscible liquids. Before apatite is saturated (Lower- and Middle Zone), melt inclusions in plagioclase represent the best available tracer of liquid compositions. The melt inclusions are fully crystallized and consist of a uniform daughter phase assemblage of highly variable modal proportions: plagioclase (42-59 %), clinopyroxene (29-41 %), ilmenite (6-9 %), magnetite (4-10%), apatite (1-9 %), and accessory phases (Skaergaard in the upper part of the Lower Zone close to the first appearance of liquidus magnetite and that the Upper Zone crystallized from an immiscible emulsion. The extent of gravitational separation of the two contrasting melts and macroscopic effects of unmixing on the Skaergaard magma remain, however, unclear. We expect to clarify these issues by

  12. Modelling Greenland icebergs

    Science.gov (United States)

    Marson, Juliana M.; Myers, Paul G.; Hu, Xianmin

    2017-04-01

    The Atlantic Meridional Overturning Circulation (AMOC) is well known for carrying heat from low to high latitudes, moderating local temperatures. Numerical studies have examined the AMOC's variability under the influence of freshwater input to subduction and deep convections sites. However, an important source of freshwater has often been overlooked or misrepresented: icebergs. While liquid runoff decreases the ocean salinity near the coast, icebergs are a gradual and remote source of freshwater - a difference that affects sea ice cover, temperature, and salinity distribution in ocean models. Icebergs originated from the Greenland ice sheet, in particular, can affect the subduction process in Labrador Sea by decreasing surface water density. Our study aims to evaluate the distribution of icebergs originated from Greenland and their contribution to freshwater input in the North Atlantic. To do that, we use an interactive iceberg module coupled with the Nucleus for European Modelling of the Ocean (NEMO v3.4), which will calve icebergs from Greenland according to rates established by Bamber et al. (2012). Details on the distribution and trajectory of icebergs within the model may also be of use for understanding potential navigation threats, as shipping increases in northern waters.

  13. Greenland from Archaean to Quaternary, Descriptive text to the 1995 Geological Map of Greenland 1:2 500 000, 2nd edition

    Directory of Open Access Journals (Sweden)

    Kalsbeek, Feiko

    2009-11-01

    Full Text Available The geological development of Greenland spans a period of nearly 4 Ga, from Eoarchaean to the Quaternary. Greenland is the largest island on Earth with a total area of 2 166 000 km2, but only c. 410 000 km2 are exposed bedrock, the remaining part being covered by a major ice sheet (the Inland Ice reaching over 3 km in thickness. The adjacent offshore areas underlain by continental crust have an area of c. 825 000 km2. Greenland is dominated by crystalline rocks of the Precambrian shield, which formed during a succession of Archaean and Palaeoproterozoic orogenic events and stabilised as a part of the Laurentian shield about 1600 Ma ago. The shield area can be divided into three distinct types of basement provinces: (1 Archaean rocks (3200–2600 Ma old, with local older units up to >3800Ma that were almost unaffected by Proterozoic or later orogenic activity; (2 Archaean terrains reworked during the Palaeoproterozoic around 1900–1750 Ma ago; and (3 terrains mainly composed of juvenile Palaeoproterozoic rocks (2000–1750 Ma in age.Subsequent geological developments mainly took place along the margins of the shield. During the Proterozoic and throughout the Phanerozoic major sedimentary basins formed, notably in North and North-East Greenland, in which sedimentary successions locally reaching 18 km in thickness were deposited. Palaeozoic orogenic activity affected parts of these successions in the Ellesmerian fold belt of North Greenland and the East Greenland Caledonides; the latter also incorporates reworked Precambrian crystalline basement complexes. Late Palaeozoic and Mesozoic sedimentary basins developed along the continent–ocean margins in North, East and West Greenland and are now preserved both onshore and offshore. Their development was closely related to continental break-up with formation of rift basins. Initial rifting in East Greenland in latest Devonian to earliest Carboniferous time and succeeding phases culminated with the

  14. Regional variation of caesium-137 in minke whales ¤Balaenoptera acutorostrata¤ from West Greenland, the Northeast Atlantic and the North Sea

    DEFF Research Database (Denmark)

    Born, E.W.; Dahlgaard, H.; Riget, F.F.

    2002-01-01

    Levels of radioactive caesium (Cs-137) were determined in minke whales (Balaenoptera acutorostrata) from West Greenland, the Northeast Atlantic region and the North Sea. The sample consisted of muscle tissue from 135 minke whales caught in 1998 in 7 different areas: West Greenland, n = 44; East G...

  15. Wireless Intrusion Prevention Systems

    Directory of Open Access Journals (Sweden)

    Jack TIMOFTE

    2008-01-01

    Full Text Available The wireless networks have changed the way organizations work and offered a new range of possibilities, but at the same time they introduced new security threats. While an attacker needs physical access to a wired network in order to launch an attack, a wireless network allows anyone within its range to passively monitor the traffic or even start an attack. One of the countermeasures can be the use of Wireless Intrusion Prevention Systems.

  16. Atuarfitsialak: Greenland's Cultural Compatible Reform

    Science.gov (United States)

    Wyatt, Tasha R.

    2012-01-01

    In 2002, Greenlandic reform leaders launched a comprehensive, nation-wide reform to create culturally compatible education. Greenland's reform work spans the entire educational system and includes preschool through higher education. To assist their efforts, reform leaders adopted the Standards for Effective Pedagogy developed at the Center for…

  17. Temperature and conductivity data collected by CTDs on moored buoys in the Sermilik Fjord, Greenland from 2008-07 to 2009-08 (NODC Accession 0123217)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data included in this dataset were collected in the Sermilik Fjord, located in East Greenland in the Ammassalik district close to the town of Tasiilaq. Data...

  18. Adventure Learning @ Greenland

    Science.gov (United States)

    Miller, B. G.; Cox, C. J.; Hougham, J.; Walden, V. P.; Eitel, K.; Albano, A.

    2013-12-01

    Teaching the general public and K-12 communities about scientific research has taken on greater importance as climate change increasingly impacts the world we live in. Science researchers and the educational community have a widening responsibility to produce and deliver curriculum and content that is timely, scientifically sound and engaging. To address this challenge, in the summer of 2012 the Adventure Learning @ Greenland (AL@GL) project, a United States' National Science Foundation (NSF) funded initiative, used hands-on and web-based climate science experiences for high school students to promote climate and science literacy. This presentation will report on an innovative approach to education and outreach for environmental science research known as Adventure Learning (AL). The purpose of AL@GL was to engage high school students in the US, and in Greenland, in atmospheric research that is being conducted in the Arctic to enhance climate and science literacy. Climate and science literacy was explored via three fundamental concepts: radiation, the greenhouse effect, and climate vs. weather. Over the course of the project, students in each location engaged in activities and conducted experiments through the use of scientific instrumentation. Students were taught science research principles associated with an atmospheric observatory at Summit Station, Greenland with the objective of connecting climate science in the Arctic to student's local environments. Summit Station is located on the Greenland Ice Sheet [72°N, 38°W, 3200 m] and was the primary location of interest. Approximately 35 students at multiple locations in Idaho, USA, and Greenland participated in the hybrid learning environments as part of this project. The AL@GL project engaged students in an inquiry-based curriculum with content that highlighted a cutting-edge geophysical research initiative at Summit: the Integrated Characterization of Energy, Clouds, Atmospheric state, and Precipitation at

  19. The Greenland analogue project. Yearly report 2010

    Energy Technology Data Exchange (ETDEWEB)

    Harper, J.; Brinkerhoff, D.; Johnson, J. [University of Montana, Missoula (United States); Ruskeeniemi, T.; Engstroem, J.; Kukkonen, I. [Geological Survey of Finland (Finland)] [and others

    2012-04-15

    A four-year field and modelling study of the Greenland ice sheet and subsurface conditions, Greenland Analogue Project (GAP), has been initiated collaboratively by SKB, Posiva and NWMO to advance the understanding of processes associated with glaciation and their impact on the long-term performance of a deep geological repository. The study site encompasses a land terminus portion of the Greenland ice sheet, east of Kangerlussuaq, and is in many ways considered to be an appropriate analogue of the conditions that are expected to prevail in much of Canada and Fennoscandia during future glacial cycles. The project begins in 2009 and is scheduled for completion in 2012. Our current understanding of the hydrological, hydrogeological and hydrogeochemical processes associated with cold climate conditions and glacial cycles, and their impact on the long-term performance of deep geological repositories for spent nuclear fuel, will be significantly improved by studying a modern analogue. The GAP will conduct the first in situ investigations of some of the parameters and processes needed to achieve a better understanding of how an ice sheet may impact a deep repository, and will provide measurements, observations and data that may significantly improve our safety assessments and risk analyses of glaciation scenarios. This report was produced by the GAP team members and presents an overview of the activities within the GAP during the interval January 1 to December 31, 2010, as well as research results obtained during this time frame. Research for the GAP is ongoing, and additional results related to the data presented here may become available in the future and will be presented in subsequent annual reports. (orig.)

  20. 新疆古伦沟地区古仍格萨拉东岩体的地球化学及锆石U-Pb年龄%Geochemistry and Zircon U-Pb Age of East Gurenggesala Granitic Intrusion in Gulungou Area, Xinjiang

    Institute of Scientific and Technical Information of China (English)

    王居里; 杨猛; 王建其; 党飞鹏

    2013-01-01

    The East Gurenggesala granitic intrusion in Gulungou area on the northern margin of Middle Tianshan Mountains consist of granodiorite-porphyry with porphyry copper mineralization. The intrusion is characterized by enrichment of alkali, with Na2O/K2O ratio changing from 1.95 to 19.00, and depletion of Fe and Mg, accompanied by sub-alkaline (mainly tholeiitic and calc-alkaline series) and weakly peraluminous features (A/CNK=0.98~1.11). REE concentrations are low (∑REE=61.28×10-6~99.50×10-6) and show obvious differentiation between LREE and HREE (LaN/YbN=7.82~22.80), with weak Eu negative anomalies (δEu=0.72~0.97). In addition, the rock mass is relatively rich in such elements as Rb, Ba, Th, U and K, and poor in Nb, Ta, P, Ti etc., suggesting characteristics of volcanic-arc granite (VAG). Zircon LA-ICP-MS U-Pb dating results show that the crystallization of the intrusion took place from (488.9±1.7) Ma to (470.5±3.1) Ma, i.e., in Early Ordovician. Sr-Nd isotopic compositions of East Gurenggesala granitic intrusion are fairly uniform: (87Sr/86Sr)i=0.70677~0.70685,εSr(t)=40.10~41.21, (143Nd/144Nd)i=0.51190~0.51191, εNd(t)=-2.62 ~ -2.30, tDM=1.31~1.38 Ga, implying that magma originated from partial melting of Meso-Proterozoic mantle-derived basic lower crust. Based on both previous and present research results, the authors have reached the conslusion that East Gurenggesala granitic intrusion was formed in the epicontinental arc relevant to the subduction of the paleo-Junggar ocean towards Yili-Central Tianshan plate in Early Ordovician together with porphyry copper mineralization. In general, the emplacement of East Gurenggesala granitic intrusion marked the epoch when the northern margin of Middle Tianshan entered into the stage of active epicontinental arc in connection with subduction in Early Ordovician.%古伦沟地区古仍格萨拉东花岗闪长斑岩体位于中天山构造带北缘。地球化学和锆石 U-P 年龄测定

  1. Miocene uplift of the NE Greenland margin linked to plate tectonics: Seismic evidence from the Greenland Fracture Zone, NE Atlantic.

    Science.gov (United States)

    Døssing, Arne; Japsen, Peter; Watts, Anthony; Nielsen, Tove; Jokat, Wilfried; Thybo, Hans

    2016-04-01

    Tectonic models predict that, following breakup, rift margins undergo only decaying thermal subsidence during their post-rift evolution. However, post-breakup stratigraphy beneath the NE Atlantic shelves shows evidence of regional-scale unconformities, commonly cited as outer margin responses to inner margin episodic uplift, including the formation of coastal mountains. The origin of these events remains enigmatic. We present a seismic reflection study from the Greenland Fracture Zone - East Greenland Ridge (GFZ-EGR) and the NE Greenland shelf. We document a regional intra-Miocene seismic unconformity (IMU), which marks the termination of syn-rift deposition in the deep-sea basins and onset of: (i) thermo-mechanical coupling across the GFZ, (ii) basin compression, and (iii) contourite deposition, north of the EGR. The onset of coupling across the GFZ is constrained by results of 2-D flexural backstripping. We explain the thermo-mechanical coupling and the deposition of contourites by the formation of a continuous plate boundary along the Mohns and Knipovich ridges, leading to an accelerated widening of the Fram Strait. We demonstrate that the IMU event is linked to onset of uplift and massive shelf-progradation on the NE Greenland margin. Given an estimated middle-to-late Miocene (~15-10 Ma) age of the IMU, we speculate that the event is synchronous with uplift of the East and West Greenland margins. The correlation between margin uplift and plate-motion changes further indicates that the uplift was triggered by plate tectonic forces, induced perhaps by a change in the Iceland plume (a hot pulse) and/or by changes in intra-plate stresses related to global tectonics.

  2. Mapping faults and intrusions onshore Disko Island by use of Vibroseismic data, shallow marine seismic data and electromagnetic observations

    Science.gov (United States)

    Clausen, Ole R.; Nørmark, Egon; Gulbrandsen, Pelle; Sabra, Henrik

    2014-05-01

    The west Greenland margin is characterized by sedimentary basins containing high density of intrusions (dikes and sills) originating from the Cenozoic breakup and separation of Greenland and North American. The magmatic rocks have lately attracted interest due to observations of hydrocarbons associated to the intrusions but here due to the ore potential associated to the same intrusions. In 2000 a marine seismic campaign by GEUS in the coastal areas of West Greenland showed that it is possible to identify magmatic intrusions in the sedimentary succession as well as map normal faults, and that the intrusions are heterogeneous distributed and probably related to the normal faults. The presence of normal faults is known from the regional onshore geological mapping campaigns performed by GEUS. However, the marine seismic data indicate a much more complicated structural pattern than presented in the onshore maps, which is a well-known phenomenon (Marcussen et al., 2002). In 2012 and 2013 seismic data were acquired onshore on the northern coast of Disko as part of a research project funded by Avannaa Resources . The objective was initially to test whether it is possible to acquire data of a quality enabling the observation and mapping of intrusions in the subsurface. Later it was followed by a more extensive survey where it was attempted to map the depth to and geometry of the intrusions. The relatively dense seismic grid onshore -compared to the marine seismic data offshore west Greenland- enable the identification and more important the mapping of several intrusions. They show some of the same characteristics as intrusions observed at e.q. the Norwegian margin of the North Atlantic (Hansen et al., 2004). The preliminary results which integrate both marine and onshore seismic data revise the structural understanding of the area and indicate a close relation between the intrusions and the rift related normal faults. The results are consistent with remote sensing methods

  3. Melting at the base of the Greenland ice sheet explained by Iceland hotspot history

    Science.gov (United States)

    Rogozhina, Irina; Petrunin, Alexey G.; Vaughan, Alan P. M.; Steinberger, Bernhard; Johnson, Jesse V.; Kaban, Mikhail K.; Calov, Reinhard; Rickers, Florian; Thomas, Maik; Koulakov, Ivan

    2016-05-01

    Ice-penetrating radar and ice core drilling have shown that large parts of the north-central Greenland ice sheet are melting from below. It has been argued that basal ice melt is due to the anomalously high geothermal flux that has also influenced the development of the longest ice stream in Greenland. Here we estimate the geothermal flux beneath the Greenland ice sheet and identify a 1,200-km-long and 400-km-wide geothermal anomaly beneath the thick ice cover. We suggest that this anomaly explains the observed melting of the ice sheet’s base, which drives the vigorous subglacial hydrology and controls the position of the head of the enigmatic 750-km-long northeastern Greenland ice stream. Our combined analysis of independent seismic, gravity and tectonic data implies that the geothermal anomaly, which crosses Greenland from west to east, was formed by Greenland’s passage over the Iceland mantle plume between roughly 80 and 35 million years ago. We conclude that the complexity of the present-day subglacial hydrology and dynamic features of the north-central Greenland ice sheet originated in tectonic events that pre-date the onset of glaciation in Greenland by many tens of millions of years.

  4. Snapshots of the Greenland ice sheet configuration in the Pliocene to early Pleistocene

    DEFF Research Database (Denmark)

    Solgaard, Anne M.; Reeh, Niels; Japsen, Peter

    2011-01-01

    from the deposits of the Kap Kobenhavn Formation, North Greenland. Our experiments show that no coherent ice sheet is likely to have existed in Greenland during the Mid-Pliocene Warmth and that only local ice caps may have been present in the coastal mountains of East Greenland. Our results illustrate......The geometry of the ice sheets during the Pliocene to early Pleistocene is not well constrained. Here we apply an ice-flow model in the study of the Greenland ice sheet (GIS) during three extreme intervals of this period constrained by geological observations and climate reconstructions. We study...... the variability of the GIS during the Pliocene to early Pleistocene and underline the importance of including independent estimates of the GIS in studies of climate during this period. We conclude that the GIS did not exist throughout the Pliocene to early Pleistocene, and that it melted during interglacials even...

  5. Toxaphene in the aquatic environment of Greenland.

    Science.gov (United States)

    Vorkamp, Katrin; Rigét, Frank F; Dietz, Rune

    2015-05-01

    The octa- and nonachlorinated bornanes (toxaphene) CHBs 26, 40, 41, 44, 50 and 62 were analysed in Arctic char (Salvelinus alpinus), shorthorn sculpin (Myoxocephalus scorpius), ringed seal (Pusa hispida) and black guillemot eggs (Cepphus grylle) from Greenland. Despite their high trophic level, ringed seals had the lowest concentrations of these species, with a Σ6Toxaphene median concentration of 13-20 ng/g lipid weight (lw), suggesting metabolisation. The congener composition also suggests transformation of nona- to octachlorinated congeners. Black guillemot eggs had the highest concentrations (Σ6Toxaphene median concentration of 971 ng/g lw). Although concentrations were higher in East than in West Greenland differences were smaller than for other persistent organic pollutants. In a circumpolar context, toxaphene had the highest concentrations in the Canadian Arctic. Time trend analyses showed significant decreases for black guillemot eggs and juvenile ringed seals, with annual rates of -5 to -7% for Σ6Toxaphene. The decreases were generally steepest for CHBs 40, 41 and 44.

  6. Greenland Telescope (GLT Project

    Directory of Open Access Journals (Sweden)

    Nakamura M.

    2013-12-01

    Full Text Available The GLT project is deploying a new submillimeter (submm VLBI station in Greenland. Our primary scientific goal is to image a shadow of the supermassive black hole (SMBH of six billion solar masses in M87 at the center of the Virgo cluster of galaxies. The expected SMBH shadow size of 40-50 μas requires superbly high angular resolution, suggesting that the submm VLBI would be the only way to obtain the shadow image. The Summit station in Greenland enables us to establish baselines longer than 9,000 km with ALMA in Chile and SMA in Hawaii as well as providing a unique u–v coverage for imaging M87. Our VLBI network will achieve a superior angular resolution of about 20 μas at 350 GHz, corresponding to ∼ 2.5 times of the Schwarzschild radius of the supermassive black hole in M87. We have been monitoring the atmospheric opacity at 230 GHz since August. 2011; we have confirmed the value on site during the winter season is comparable to the ALMA site thanks to high altitude of 3,200 m and low temperature of −50°C. We will report current status and future plan of the GLT project towards our expected first light on 2015–2016.

  7. Seabird Colonies in Western Greenland

    DEFF Research Database (Denmark)

    Boertmann, D.; Mosbech, A.; Falk, K.;

    surveys of seabird colonies are needed, due to a lack of information or because the present information probably is outdated. The most immediate threats to the colonial seabirds in western Greenland during the breeding time is hunting and egging. Oil pollution is a minor threat to-day, but will increase...... if offshore areas with oil potential are explored and developed. Tab. 6 gives an overview of each species sensitivity to oil spills and the capacity to recover, as well as a comparison of the western Greenland population numbers to the North Atlantic population numbers. The most significant western Greenland...

  8. Extreme iron enrichment and liquid immiscibility in mafic intrusions: Experimental evidence revisited

    Science.gov (United States)

    Veksler, Ilya V.

    2009-07-01

    This paper examines phase equilibria and mass balance constraints on Fe enrichment in tholeiitic liquids in plutonic environments. The peak of Fe enrichment is thought to roughly coincide with magma saturation in Fe-Ti oxides; and olivine starts to react with the liquid at about the same time. This crucial stage of crystallization is examined in detail using a compilation of chemical analyses of 64 experimental charges that comprise liquids (quenched glasses) equilibrated with the liquidus assemblage of olivine, plagioclase, high-Ca pyroxene, and low-Ca pyroxene. Some samples also contain Fe-Ti oxides. It is shown that the 4-phase liquidus assemblage does not constrain a narrow range of liquid compositions. The concentrations of SiO 2 in the selection of experimental glasses vary broadly from 42 to 66 wt.%. Silica content shows strong negative correlations with FeO and CaO/Al 2O 3, and strong positive correlation with alkalis. Extreme Fe enrichment above 22 wt.% FeO is observed only in alkali-free or alkali-poor liquids. Broad compositional variations for the multiply-saturated liquids are attributed to strong non-ideality and complex concentration-activity relationships in ferrobasaltic melts. Liquid immiscibility characteristic of Fe-rich silicate liquids is the ultimate consequence of non-ideality. Petrogenetic implications of phase equilibria and mass balance constraints are discussed for a classical example of the Skaergaard intrusion in East Greenland, where the trend of extreme Fe enrichment has been in contention. It is proposed that seemingly conflicting results of experiments on Skaergaard natural cumulate rocks and model melt compositions can be reconciled if it is assumed that silicate liquid immiscibility in Skaergaard started not at the very end of crystallization but earlier, soon after the start of ilmenite and magnetite crystallization.

  9. An evaluation of teeth of ringed seals (Phoca hispida) from Greenland as a matrix to monitor spatial and temporal trends of mercury and stable isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Aubail, Aurore, E-mail: aaubail@yahoo.fr [National Environmental Research Institute, Aarhus University, Frederiksborgvej 399, P.O. Box 358, DK-4000 Roskilde (Denmark); Littoral, Environnement et Societes (LIENSs), UMR 6250, CNRS-Universite de La Rochelle, 2 rue Olympe de Gouges, F-17000 La Rochelle (France); Dietz, Rune; Riget, Frank [National Environmental Research Institute, Aarhus University, Frederiksborgvej 399, P.O. Box 358, DK-4000 Roskilde (Denmark); Simon-Bouhet, Benoit; Caurant, Florence [Littoral, Environnement et Societes (LIENSs), UMR 6250, CNRS-Universite de La Rochelle, 2 rue Olympe de Gouges, F-17000 La Rochelle (France)

    2010-10-01

    Total mercury (Hg) concentrations were measured in teeth of ringed seals from Qeqertarsuaq, central West Greenland (1982 to 2006) and Ittoqqortoormiit, central East Greenland (1986 to 2006). Stable isotopic ratios of carbon ({sup 13}C/{sup 12}C) and nitrogen ({sup 15}N/{sup 14}N) were determined as well to provide insights into diet variations between regions or through time. Mercury concentrations decreased the first years of life of the animals suggesting that Hg had been transferred from the mother to the foetus and newborn. The Hg concentrations in teeth were significantly lesser in ringed seals from central West Greenland compared to those from central East Greenland. Carbon and nitrogen stable isotopic values measured in the animals differed also significantly between the two regions. Increasing temporal trends of dental Hg concentrations between 1994 and 2006 were observed in ringed seals from both central West Greenland and central East Greenland. These increases were attributed to global changes in environmental Hg levels since no temporal trends in {delta}{sup 15}N values were found to support the hypothesis of a diet shift over time. Furthermore, a decreasing temporal trend in {delta}{sup 13}C values was observed in the teeth of seals from central East Greenland, and explained by a likely change over time towards more pelagic feeding habits; alternatively, the so-known Seuss effect was thought to be responsible for this decrease. Finally, it was concluded that the tooth of ringed seal was a good monitoring tissue to assess Hg trends.

  10. An evaluation of teeth of ringed seals (Phoca hispida) from Greenland as a matrix to monitor spatial and temporal trends of mercury and stable isotopes.

    Science.gov (United States)

    Aubail, Aurore; Dietz, Rune; Rigét, Frank; Simon-Bouhet, Benoît; Caurant, Florence

    2010-10-01

    Total mercury (Hg) concentrations were measured in teeth of ringed seals from Qeqertarsuaq, central West Greenland (1982 to 2006) and Ittoqqortoormiit, central East Greenland (1986 to 2006). Stable isotopic ratios of carbon ((13)C/(12)C) and nitrogen ((15)N/(14)N) were determined as well to provide insights into diet variations between regions or through time. Mercury concentrations decreased the first years of life of the animals suggesting that Hg had been transferred from the mother to the foetus and newborn. The Hg concentrations in teeth were significantly lesser in ringed seals from central West Greenland compared to those from central East Greenland. Carbon and nitrogen stable isotopic values measured in the animals differed also significantly between the two regions. Increasing temporal trends of dental Hg concentrations between 1994 and 2006 were observed in ringed seals from both central West Greenland and central East Greenland. These increases were attributed to global changes in environmental Hg levels since no temporal trends in delta(15)N values were found to support the hypothesis of a diet shift over time. Furthermore, a decreasing temporal trend in delta(13)C values was observed in the teeth of seals from central East Greenland, and explained by a likely change over time towards more pelagic feeding habits; alternatively, the so-known Seuss effect was thought to be responsible for this decrease. Finally, it was concluded that the tooth of ringed seal was a good monitoring tissue to assess Hg trends.

  11. Regional and inter annual patterns of heavy metals, organochlorines and stable isotopes in narwhals (Monodon monoceros) from West Greenland

    DEFF Research Database (Denmark)

    Dietz, R.; Riget, F.; Hobson, K.A.

    2004-01-01

    , indicating a temporal decrease of SigmaPCBs. SigmaPCBs, DDTs, HCHs and toxaphenes seem to be at similar levels in West Greenland and Arctic Canada, which can be explained by the close winter distributions of populations as well as large ranges in concentrations, time span, number of analyses and the size....../age composition of the data. PCB and DDT concentrations in West Greenland narwhals were half those found in East Greenland and Svalbard. Stable-carbon isotope ratios in muscle of 150 narwhals showed a decreasing trend in the first year when they gradually reduced their dependency on mother's milk, after which...

  12. Shrub expansion in SW Greenland

    DEFF Research Database (Denmark)

    Jørgensen, Rasmus Halfdan

    from more southerly habitats are better adapted to climatic conditions in a warmer Greenland compared with local provenances. To answer the first question historical photographs of vegetation in SW Greenland (1898–1974) were compiled. The photos were repeated in 2010 and 2011 and 64 photo pairs were...... cropped into 133 smaller units and classified by aspect, substrate stability, muskoxen grazing and human disturbance. The photo material was evaluated by 22 experts with respect to changes in shrub cover. The results revealed a general shrub cover increase in the whole dataset, but also in a subset...... of firewood collection. A delayed reaction to the ending of the little ice age cannot be excluded, but seems rather unlikely considering other studies from Greenland. Effects of global warming in SW Greenland must be studied over even longer time periods than the 120 years of the current study. To answer...

  13. Why is Transparency Greenland Necessary?

    DEFF Research Database (Denmark)

    Jensen, Boris Brorman

    2012-01-01

    Greenland is facing significant changes in the composition of its economy, and is moving rapidly in the direction of becoming a commodities economy. Studies conducted by Transparency International in other parts of the world suggest that oil exploration and mining are among the areas of economic...... activity, which carry the greatest risk of corruption. It is therefore important that Greenlandic society is prepared for the new economic players, and the risks this may entail....

  14. Intrusive growth of sclerenchyma fibers

    NARCIS (Netherlands)

    Snegireva, A.V.; Ageeva, M.V.; Amenitskii, S.I.; Chernova, T.E.; Ebskamp, M.; Gorshkova, T.A.

    2010-01-01

    Intrusive growth is a type of cell elongation when the rate of its longitudinal growth is higher than that of surrounding cells; therefore, these cells intrude between the neighboring cells penetrating the middle lamella. The review considers the classical example of intrusive growth, e.g., elongati

  15. Solvents and vapor intrusion pathways.

    Science.gov (United States)

    Phillips, Scott D; Krieger, Gary R; Palmer, Robert B; Waksman, Javier C

    2004-08-01

    Vapor intrusion must be recognized appropriately as a separate pathway of contamination. Although many issues resemble those of other forms of contamination (particularly its entryway, which is similar to that of radon seepage), vapor intrusion stands apart as a unique risk requiring case-specific action. This article addresses these issues and the current understanding of the most appropriate and successful remedial actions.

  16. Bathymetry of Greenland Fjords

    Science.gov (United States)

    Cochran, J. R.; Boghosian, A.; Tinto, K. J.; Bell, R. E.; Porter, D. F.

    2013-12-01

    Operation IceBridge (OIB) has performed extensive airborne gravity surveys of Greenlandic fjords in order to model their bathymetry. Bathymetry inversions from gravity data provide a model of the fjord bathymetry in areas that are otherwise difficult to survey. We use these gravity surveys along with other OIB datasets to create bathymetry models for fjords surveyed by OIB from 2009-2012. These models allow us to estimate depths to the grounding line in areas with poor radar returns and sill depths and overdeepenings in the fjords. Models have been constructed by combining ice-surface and ice-thickness data from coincident OIB lidar and radar surveys. The inversion of gravity anomalies to bathymetry models is dependent on assumptions of both local and regional variations in geology. Local variations can often be identified with OIB magnetic anomalies. Regional geoid variations produce long-wavelength gravity anomalies that are part of the observed gravity, but not present in the forward modeled gravity over the known bed. This effect varies in magnitude around Greenland. In long fjords, removing the long-wavelength components of the observed anomalies reduces the uncertainties from regional geological variations. The average combined error for absolute model depths varies regionally between 50 m and 200 m. The error budget takes into account the measurement uncertainty of the gravity survey along with sensitivity of the model to regional gravity corrections and the point at which the model is pinned to known bed. Gravity inversions model bathymetry at ~5 km wavelengths, while bed topography onshore is known at a higher resolution from radar surveys. This change of length scale must be taken into account when using bathymetry models to consider grounding line morphology as well as when combining modeled bathymetry with offshore bathymetric data. Models can be improved by pinning to ship surveys of offshore bathymetry. Our dataset has incorporated available offshore

  17. Penile density and globally used chemicals in Canadian and Greenland polar bears

    DEFF Research Database (Denmark)

    Sonne, Christian; Dyck, Markus; Rigét, Frank F

    2015-01-01

    could be in a range that may lead to disruption of normal reproduction and development. It is therefore likely that EDCs directly affect development and bone density in polar bears. Canadian bears had in general the best health and the North East Greenland subpopulation being at the highest risk...

  18. Mineralogy and geochemistry of REE-Zr-Nb mineralised nepheline syenites in the peralkaline Ilímaussaq complex, South Greenland

    DEFF Research Database (Denmark)

    Borst, Anouk Margaretha

    for these elements. This thesis focusses on the Mesoproterozoic Ilímaussaq complex (c. 1160 ± 5 Ma) in Southern Greenland, a well-known alkaline intrusion that hosts significant resources of REE, as well as zirconium, niobium, tantalum, uranium, lithium and zinc. The Ilímaussaq complex is part of the rift...

  19. Controls on magmatic PGE and Au mineralization in the Skaergaard Intrusion

    Science.gov (United States)

    Keays, Reid; Tegner, Christian

    2013-04-01

    The Skaergaard Intrusion of East Greenland is the host for significant magmatic PGE and Au mineralization (the Platinova Reefs). It was formed from a single batch of magma that crystallized in its entirety as a closed system. Unlike all other examples of significant magmatic PGE and Ni-Cu-PGE mineralization, the Skaergaard rocks exhibit no evidence of crustal contamination, the major factor responsible for driving magmas to sulphide saturation and ore genesis. Although the Skaergaard rocks and mineralized zones have extremely low S contents, the mineralization is believed to be the product of late stage sulphide saturation of the magma. Three factors drove the magma to sulphide saturation, viz: (1) prolonged build up of S in the residual melt of the fractionating magma; (2) crystallization of magnetite which slowed down the build up of FeO in the fractionating magma; and (3) cooling of the magma against the walls of the intrusion. High quality PGE, Au, Cu, S, Se data and other geochemical data for samples from a detailed stratigraphic section through the Skaergaard intrusion are used to model these elements throughout its crystallization history, estimate their concentrations in the Skaergaard parental magma, and to establish the timing of sulphide saturation and the causes of PGE-Au mineralization. The model indicates that the parental magma contained 4.0 ppb Au, 18.7 ppb Pd, 9.0 ppb Pt, 95 ppb Se and 240 ppm Cu. The high Pd/Pt ratio indicates that the magma had undergone a significant amount of fractionation prior to entry into the Skaergaard magma chamber, consistent with the silicate mineralogy. A sharp increase in PGE contents (but not Cu or incompatible lithophile trace elements) 300m below the Platinova Reefs coincides with the first appearance of cumulus magnetite and marks the stratigraphic position at which tiny amounts of cumulus PGE-rich sulphides segregated from the magma. Although the S contents of all rocks below the Platinova Reefs are below the

  20. Post-colonial identity in Greenland?

    DEFF Research Database (Denmark)

    Gad, Ulrik Pram

    2009-01-01

    could be furthered by bringing politics back in. Based on a discourse analysis of the Greenlandic debate on language, this paper makes three claims: First, the identity projects promoted in Greenland are based on an essentialist conception of identity. Secondly, Greenlandic identity discourse combines......In the gradual unravelling of Greenland’s colonial relationship to Denmark, an essentialist conceptualization of Greenlandic identity has played a significant role. However, both our scholarly understanding of post-colonial Greenlandic identity and the process towards independence for Greenland...... elements of traditional Inuit culture and elements of colonial modernity. Thirdly, monolingual Greenlanders are those with the most to gain from abandoning the dichotomy of essentialist identities. Strategically, the paper suggests a post-post-colonial Greenlandic identity as a means of avoiding...

  1. Problems concerning musk oxen in Greenland

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes the range of muskox in Greenland. The predominant habitat of the muskox is in northern and northeastern Greenland; however, it has appeared...

  2. Post-colonial identity in Greenland?

    DEFF Research Database (Denmark)

    Gad, Ulrik Pram

    2009-01-01

    In the gradual unravelling of Greenland’s colonial relationship to Denmark, an essentialist conceptualization of Greenlandic identity has played a significant role. However, both our scholarly understanding of post-colonial Greenlandic identity and the process towards independence for Greenland...... could be furthered by bringing politics back in. Based on a discourse analysis of the Greenlandic debate on language, this paper makes three claims: First, the identity projects promoted in Greenland are based on an essentialist conception of identity. Secondly, Greenlandic identity discourse combines...... elements of traditional Inuit culture and elements of colonial modernity. Thirdly, monolingual Greenlanders are those with the most to gain from abandoning the dichotomy of essentialist identities. Strategically, the paper suggests a post-post-colonial Greenlandic identity as a means of avoiding...

  3. Inuit dietary patterns in modern Greenland

    DEFF Research Database (Denmark)

    Bjerregaard, Peter; Jeppesen, Charlotte

    2010-01-01

    The purpose of the study was to apply two different approaches of dietary pattern definition to data from Greenland and to analyse the contemporary dietary patterns of the Inuit in Greenland in relation to urbanization and socio-economic positions.......The purpose of the study was to apply two different approaches of dietary pattern definition to data from Greenland and to analyse the contemporary dietary patterns of the Inuit in Greenland in relation to urbanization and socio-economic positions....

  4. Granitoid intrusions and related deposits

    Institute of Scientific and Technical Information of China (English)

    孟良义; 李绪俊

    1996-01-01

    Taking the Bainaimiao copper and gold deposits, Inner Mongolia and the Wushan copper deposits, Jiangxi Province as examples, a discussion is devoted to the relationship between the granitoid intrusions and related deposits from different lines of evidence: the spatial distribution, country rocks and alteration of the deposits, trace element contents and vertical zoning of elements in deposits, the metallogenic preference of granitoid intrusions, the metallogenic models and stable isotopic geology. It is concluded that the ore-bearing fluids mainly come from granitoid magmas and granitoid intrusions are closely associated with the related deposits in space.

  5. Novel Model for Intrusion Detection

    Institute of Scientific and Technical Information of China (English)

    Li Jia-chun; Li Zhi-tang

    2003-01-01

    It's very difficult that the traditional intrusion detection methods based on accurate match adapt to the blur and uncertainty of user information and expert knowledge, it results in failing to report the variations of attack signature. In addition security itself includes fuzziness, the judgment standard of confidentiality, integrity and availability of system resource is uncertain. In this paper fuzzy intrusion detection based on partial match is presented to detect some types of attacks availably and alleviate some of the difficulties of above approaches, the architecture of fuzzy intrusion detection system(FIDS) is introduced and its performance is analyzed.

  6. Novel Model for Intrusion Detection

    Institute of Scientific and Technical Information of China (English)

    Li; Jia-chun; Li; Zhi-tang

    2003-01-01

    It's very difficult that the traditional intrusion detection methods based on accurate match adapt to the blur and uncertainty of user information and expert knowledge, it results in failing to report the variation of attack signature.In addition security itself includes fuzziness, the judgment standard of confidentiality, integrity and availability of system resource is uncertain. In this paper fuzzy intrusion detection based on partial match is presented to detect some types of attacks availably and alleviate some of the difficulties of above approaches, the architecture of fuzzy intrusion detection system(FIDS) is introduced and its performance is analyzed.

  7. Tectono-magmatic evolution of the younger Gardar southern rift, South Greenland

    Directory of Open Access Journals (Sweden)

    Brian G.J. Upton

    2013-11-01

    Full Text Available The 1300–1140 Ma Gardar period in South Greenland involved continental rifting, sedimentation and alkaline magmatism. The latest magmatism was located along two parallel rift zones, Isortoq–Nunarsuit in the north and the Tuttutooq–Ilimmaasaq–Narsarsuaq zone in the south addressed here. The intrusive rocks crystallised at a depth of <4 km and are essentially undisturbed by later events. Magmatism in the southern zone began with the emplacement of two giant, ≤800 m wide dykes and involved intrusion of transitional olivine basaltic, high Al/Ca magmas crystallising to troctolitic gabbros. These relatively reduced magmas evolved through marked iron enrichment to alkaline salic differentiates. In the Older giant dyke complex, undersaturated augite syenites grade into sodalite foyaite. The larger, c. 1163 Ma Younger giant dyke complex (YGDC mainly consists of structureless troctolite with localised developments of layered cumulates. A layered pluton (Klokkenis considered to be coeval and presumably comagmatic with the YGDC. At the unconformitybetween the Ketilidian basement and Gardar rift deposits, the YGDC expanded into a gabbroic lopolith. Its magma may represent a sample from a great, underplated mafic magma reservoir, parental to all the salic alkaline rocks in the southern rift. The bulk of these are silica undersaturated; oversaturated differentiates are probably products of combined fractional crystallisation and crustalassimilation.A major dyke swarm 1–15 km broad was intruded during declining crustal extension, with decreasing dyke widths and increasing differentiation over time. Intersection of the dyke swarm and E–W-trending sinistral faults controlled the emplacement of at least three central complexes (Narssaq, South Qôroq and early Igdlerfigssalik. Three post-extensional complexes (Tugtutôq,Ilímaussaq and late Igdlerfigssalik along the former rift mark the end of magmatism at c. 1140 Ma. The latter two complexes have

  8. Population Structure of West Greenland Narwhals

    DEFF Research Database (Denmark)

    Riget, F.; Dietz, R.; Møller, P.;

    The hypothesis that different populations of narwhals in the West Greenland area exist has been tested by different biomarkers (metal and organochlorine concentrations, stable isotopes and DNA). Samples of muscle, liver, kidney, blubber and skin tissues of narwhals from West Greenland have been...... isotopes could not support the population structure with two West Greenland populations suggested by the genetic study....

  9. Sustainable Mobile Tourist Hut for Greenland

    DEFF Research Database (Denmark)

    Qu, Jing; Villumsen, O.; Villumsen, Arne

    Greenland is experiencing growing tourism in recent years, which increases demand for tourists’ accommodation. Small huts are a traditional way for overnight stays in Greenland due to scattered population and lack of infrastructure. However, the existing huts in Greenland cannot provide satisfact...

  10. Gravity gradient for Greenland and its tectonic interpretation

    Science.gov (United States)

    Grushinsky, Andrew N.

    2013-04-01

    Gravity gradient is the indicator of the stress conditions in the lithosphere. The axis of gradient signs changing indicates the boundary of blocks exposed to different tensions. The lines of maxima and minima of gravity gradient correspondingly marked the boundary of zones of compression and expansion. Four various types of the gravity anomalies was calculated: in free air, Bouguer's, Glennie's and isostatic. And then was calculated their gradients. The preliminary analysis of gradients shows, that its qualitative behavior for all types of gravity anomalies is very closely and, therefore, conclusions about the stress conditions in the lithosphere of the considering region are definite. Range of the changing for gradients of gravity in free air anomalies - from -96.1 to 135.8 eötvös, and for gradients of gravity Bouguer's anomalies - from -122.6 to 141.9 eötvös. Range of the changing for gradients of gravity Glennie's and isostatic anomalies are substantially smaller, for gradients of gravity Glennie's anomalies - from -27.6 to 25.5 eötvös, and for gradients of gravity isostatic anomalies - from -19.2 to 21.2 eötvös. This difference in the gradient values, evidently, connects with the difference in the thoroughness and the degree of averaging of the anomalies. Analysis of gravity gradient shown the following: 1. In the western part of the researching region are distinguished three linear structures (two maxima and one minimum), which marked rift zone of the Baffin Bay and Davis Strait. This disappeared rift characterized by depressed zone, lengthened from Nares strait along the west sea coast of Greenland. In the south part of this zone localized deep fault, which northward become lesser expressed. To the north and north-east from the Nares strait lengthened to the North Pole zone of compression, blocked up existing previously rift, by which the rotation of the Greenland part of Canadian shield from its cardinal part happened. Center of this rotation

  11. Crystallization sequence of the Upper Border Series of the Skaergaard Intrusion: revised subdivision and implications for chamber-scale magma homogeneity

    Science.gov (United States)

    Salmonsen, Lars Peter; Tegner, Christian

    2013-06-01

    Although it is one of the best-studied layered mafic intrusions in the world, the crystallization sequence of the Skaergaard Intrusion, east Greenland, remains in debate. In particular, it has been argued that the crystallization sequence in the Upper Border Series, which crystallized downwards from the roof of the magma chamber, differs from that in the Layered Series formed at the floor. The proposed deviation would require chemical stratification of the magma, and a reexamination of the crystallization sequence therefore has important implications for understanding the dynamics of the system. Here, we examine a new sample set from the Upper Border Series, combining field observations, petrography and anorthite contents of plagioclase with bulk rock Ti, V, P, Cu and Mn concentrations. We demonstrate that the first phases on the liquidus were plagioclase and olivine followed by augite, then ilmenite and magnetite (simultaneously), sulfides, apatite and finally ferrobustamite (now inverted to hedenbergite). This crystallization sequence represents extreme differentiation along the tholeiitic trend, and it mirrors those at the floor (Layered Series) and walls (Marginal Border Series). We therefore propose a revised subdivision of the Upper Border Series into equivalents of the subzones in the Layered Series denoted by apostrophes (LZa', LZb', etc.). Moreover, the first appearance of each of the cumulus phases occurs at similar plagioclase core anorthite contents. The mirror images of the crystallization sequences and the anorthite contents of plagioclase cores in the three series imply that the Skaergaard magma chamber solidified by in situ crystallization along the floor, walls and roof from one, largely homogenous, convecting magma body.

  12. Children in Greenland

    DEFF Research Database (Denmark)

    Kløvgaard, Marius; Nielsen, Nina Odgaard; Sørensen, Thomas Lund

    2016-01-01

    for respiratory tuberculosis accounted 6.2:1,000, primary care non-disease (Z-diagnosis) 2,081:1,000 annually. Complete adherence to the child vaccination programme was seen in 40%, while 5% did not receive any vaccinations. CONCLUSIONS: In this first study of its kind, the health care contact pattern...... cohorts. METHODS AND DESIGN: In a retrospective, descriptive follow-up of the Ivaaq (The Greenland Child Cohort) and the CLEAR (climate changes, environmental contaminants and reproductive health) birth cohorts (total n=1,000), we reviewed medical records of children aged 6-10 in 2012 with residence...... contacts was 12,471 equalling 4.6 contacts per child per year. The annual incidence rate of hospital admissions was 1:10 children (total n=266, 1,220 days, 4.6 days/admission), outpatient contacts 2:10 children and primary care 3.6 per child. Contacts were overall more frequent in boys compared with girls...

  13. Insect-Based Holocene (and Last Interglacial?) Paleothermometry from the E and NW Greenland Ice Sheet Margins: A Fly's-Eye View of Warmth on Greenland

    Science.gov (United States)

    Axford, Y.; Bigl, M.; Carrio, C.; Corbett, L. B.; Francis, D. R.; Hall, B. L.; Kelly, M. A.; Levy, L.; Lowell, T. V.; Osterberg, E. C.; Richter, N.; Roy, E.; Schellinger, G. C.

    2013-12-01

    Here we present new paleotemperature reconstructions based upon insect (Chironomidae) assemblages and other proxies from lake sediment cores recovered in east Greenland at ~71° N near Scoresby Sund and in northwest Greenland at ~77° N near Thule/Qaanaaq. In east Greenland, Last Chance Lake (informal name) is a small, non-glacial lake situated ~90 km east of the Greenland Ice Sheet margin. The lake preserves a sedimentary record of the entire Holocene (Levy et al. 2013). Chironomids from Last Chance Lake record cold summer temperatures (and establishment of a cold-climate fauna including abundant Oliveridia and Pseudodiamesa) during the late Holocene, preceded by summer temperatures estimated to have been 3 to 6°C warmer during the first half of the Holocene (when summer insolation forcing was greater than today). In northwest Greenland, Delta Sø and Wax Lips Lake (informal name) both preserve Holocene sediments. Here we discuss the late Holocene chironomid record from Delta Sø, whereas from Wax Lips Lake (a small, non-glacial lake situated ~2 km west of the ice sheet margin) we present a longer sedimentary and biostratigraphic record. The deeper portions of cores from Wax Lips Lake yield pre-Holocene and nonfinite radiocarbon ages, suggesting that this lake preserves sediments predating the Last Glacial Maximum. Abundant chironomids in the pre-glacial sediments appear to record interglacial conditions, and we infer that these sediments may date to the Last Interglacial (Eemian). The preservation of in situ Last Interglacial lacustrine sediments so close to the modern ice sheet margin suggests a minimally erosive glacierization style throughout the last glacial period, like that inferred for other Arctic locales such as on Baffin Island (Briner et al. 2007), ~750 km southwest of our study site. Our study sites are situated nearby key ice core sites (including NEEM, Camp Century, Agassiz and Renland) and very close to the ice sheet margin. These chironomid

  14. The APEX-related RINK project in Greenland in 2010 and 2011 – a report

    DEFF Research Database (Denmark)

    Funder, Svend Visby; Kjær, Kurt H.; Larsen, Nicolaj

    for their Holocene organic sediments as part of our research into sedDNA and, combined with geochemical parameters, its use as climatic and environmental proxy. Among these lakes was Johs Iversen Sø, one of the most extensively investigated lakes in Greenland. The field work also comprised a revision...... of the deglaciation history of this area, using exposure samples from large valley systems in this area of alpine and heavily dissected topography, and OSL dating of large deglacial sediment accumulations. Another group (2 persons/3 weeks) worked along the same lines in Sermilik Fjord in south-east Greenland...

  15. Temperature, conductivity, and water currents data collected by CTDs and current meters on moored buoys in the Sermilik Fjord, Greenland from 2011-08-20 to 2012-09-16 (NODC Accession 0126772)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data included in this dataset were collected in the Sermilik Fjord, located in East Greenland in the Ammassalik district close to the town of Tasiilaq. Data...

  16. Water Temperature, conductivity, and currents data collected by CTDs and current meters on moored buoys in the Sermilik Fjord, Greenland from 2012-09-18 to 2013-08-20 (NCEI Accession 0127325)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data included in this dataset were collected in the Sermilik Fjord, located in East Greenland in the Ammassalik district close to the town of Tasiilaq. Data...

  17. Temperature and conductivity, and water currents data collected by CTDs and current meters on moored buoys in the Sermilik Fjord, Greenland from 2010-08 to 2011-08 (NODC Accession 0123282)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data included in this dataset were collected in Sermilik Fjord, located in East Greenland in the Ammassalik district close to the town of Tasiilaq. Data...

  18. Crustal structure beneath Eastern Greenland

    DEFF Research Database (Denmark)

    Reiche, Sönke; Thybo, H.; Kaip, G.

    2011-01-01

    is recorded by 350 Reftek Texan receivers for 10 equidistant shot points along the profile. We use forward ray tracing modelling to construct a two-dimensional velocity model from the observed travel times. These results show the first images of the subsurface velocity structure beneath the Greenland ice...... these mountain belts is needed for assessing the isostatic balance of the crust and to gain insight into possible links between crustal composition, rifting history and present-day topography of the North Atlantic Region. However, the acquisition of geophysical data onshore Greenland is logistically complicated...

  19. Recent advances in vapor intrusion site investigations.

    Science.gov (United States)

    McHugh, Thomas; Loll, Per; Eklund, Bart

    2017-02-22

    Our understanding of vapor intrusion has evolved rapidly since the discovery of the first high profile vapor intrusion sites in the late 1990s and early 2000s. Research efforts and field investigations have improved our understanding of vapor intrusion processes including the role of preferential pathways and natural barriers to vapor intrusion. This review paper addresses recent developments in the regulatory framework and conceptual model for vapor intrusion. In addition, a number of innovative investigation methods are discussed.

  20. Greenland Ice Sheet Melt from MODIS and Associated Atmospheric Variability

    Science.gov (United States)

    Hakkinen, Sirpa; Hall, Dorothy K.; Shuman, Christopher A.; Worthen, Denise L.; DiGirolamo, Nicolo E.

    2014-01-01

    Daily June-July melt fraction variations over the Greenland Ice Sheet (GIS) derived from the MODerate-resolution Imaging Spectroradiometer (MODIS) (2000-2013) are associated with atmospheric blocking forming an omega-shape ridge over the GIS at 500hPa height (from NCEPNCAR). Blocking activity with a range of time scales, from synoptic waves breaking poleward ( 5 days) to full-fledged blocks (5 days), brings warm subtropical air masses over the GIS controlling daily surface temperatures and melt. The temperature anomaly of these subtropical air mass intrusions is also important for melting. Based on the largest MODIS melt years (2002 and 2012), the area-average temperature anomaly of 2 standard deviations above the 14-year June-July mean, results in a melt fraction of 40 or more. Summer 2007 had the most blocking days, however atmospheric temperature anomalies were too small to instigate extreme melting.

  1. How stratospheric are deep stratospheric intrusions? LUAMI 2008

    Science.gov (United States)

    Trickl, Thomas; Vogelmann, Hannes; Fix, Andreas; Schäfler, Andreas; Wirth, Martin; Calpini, Bertrand; Levrat, Gilbert; Romanens, Gonzague; Apituley, Arnoud; Wilson, Keith M.; Begbie, Robert; Reichardt, Jens; Vömel, Holger; Sprenger, Michael

    2016-07-01

    A large-scale comparison of water-vapour vertical-sounding instruments took place over central Europe on 17 October 2008, during a rather homogeneous deep stratospheric intrusion event (LUAMI, Lindenberg Upper-Air Methods Intercomparison). The measurements were carried out at four observational sites: Payerne (Switzerland), Bilthoven (the Netherlands), Lindenberg (north-eastern Germany), and the Zugspitze mountain (Garmisch-Partenkichen, German Alps), and by an airborne water-vapour lidar system creating a transect of humidity profiles between all four stations. A high data quality was verified that strongly underlines the scientific findings. The intrusion layer was very dry with a minimum mixing ratios of 0 to 35 ppm on its lower west side, but did not drop below 120 ppm on the higher-lying east side (Lindenberg). The dryness hardens the findings of a preceding study ("Part 1", Trickl et al., 2014) that, e.g., 73 % of deep intrusions reaching the German Alps and travelling 6 days or less exhibit minimum mixing ratios of 50 ppm and less. These low values reflect values found in the lowermost stratosphere and indicate very slow mixing with tropospheric air during the downward transport to the lower troposphere. The peak ozone values were around 70 ppb, confirming the idea that intrusion layers depart from the lowermost edge of the stratosphere. The data suggest an increase of ozone from the lower to the higher edge of the intrusion layer. This behaviour is also confirmed by stratospheric aerosol caught in the layer. Both observations are in agreement with the idea that sections of the vertical distributions of these constituents in the source region were transferred to central Europe without major change. LAGRANTO trajectory calculations demonstrated a rather shallow outflow from the stratosphere just above the dynamical tropopause, for the first time confirming the conclusions in "Part 1" from the Zugspitze CO observations. The trajectories qualitatively explain

  2. Miocene uplift of the NE Greenland margin linked to plate tectonics: Seismic evidence from the Greenland Fracture Zone, NE Atlantic

    DEFF Research Database (Denmark)

    Døssing Andreasen, Arne; Japsen, Peter; Watts, Anthony B.

    2016-01-01

    Tectonic models predict that, following breakup, rift margins undergo only decaying thermal subsidence during their post-rift evolution. However, post-breakup stratigraphy beneath the NE Atlantic shelves shows evidence of regional-scale unconformities, commonly cited as outer margin responses to ...... by plate tectonic forces, induced perhaps by a change in the Iceland plume (a hot pulse) and/or by changes in intra-plate stresses related to global tectonics.......Tectonic models predict that, following breakup, rift margins undergo only decaying thermal subsidence during their post-rift evolution. However, post-breakup stratigraphy beneath the NE Atlantic shelves shows evidence of regional-scale unconformities, commonly cited as outer margin responses...... to inner margin episodic uplift, including the formation of coastal mountains. The origin of these events remains enigmatic. We present a seismic reflection study from the Greenland Fracture Zone – East Greenland Ridge (GFZ-EGR) and the NE Greenland shelf. We document a regional intra-Miocene seismic...

  3. A new interpretation of the structure of the Sept Iles Intrusive suite, Canada

    Science.gov (United States)

    Higgins, Michael D.

    2005-08-01

    The layered mafic intrusion at Sept Iles, Canada, is one of the largest intrusions in the world. A new interpretation of its structure is proposed, based on a review of its geology and a comparison with the Skaergaard intrusion, Greenland. Several different magmatic components are recognized; hence the name Sept Iles Intrusive suite (SIIS) is proposed. Emplacement of the suite may have been preceded by eruption of flood basalts. The first magmas of the suite rose in the crust to accumulate beneath the density filter afforded by the basalts. The largest component is the Sept Iles Mafic intrusion (SIMI). The Lower series of the SIMI is dominated by leucotroctolites and leucogabbros. Above it lie the Layered series, which is largely comprised of gabbro and troctolite. Both these units are unchanged from earlier interpretations. The anorthosites (s.l.), gabbros and monzogabbros, formerly called the Transitional series, are now considered to be the Upper Border series, developed by floatation of plagioclase. Common autoliths in the Layered series are parts of the hydrothermally altered Upper Border series from towards the interior of the intrusion, which have foundered and settled through the magma. The contamination of the magma that accompanied this event oxidised iron in the magma and led to the precipitation of magnetite around the periphery of the intrusion. The subsequent depletion of Fe 3+ and/or increase in SiO 2, CaO and P 2O 5 may have induced apatite saturation and accumulation to form two layers rich in apatite, near the base and at top of the Layered series. Granitic magma was developed by fractional crystallisation and was emplaced along the roof of the chamber, where it acquired large quantities of xenoliths. These were probably derived from the flood basalts, their evolved members and fragments of mafic dykes chilled by the granitic magma. Accumulations of monzonite pillows in this unit testify to another magmatic event and a floor to the granitic magma

  4. Gestational diabetes mellitus in Greenland

    DEFF Research Database (Denmark)

    Pedersen, Michael Lynge; Olesen, Jesper; Jørgensen, M. E.

    2016-01-01

    Background. Within the last 20 years, the prevalence of gestational diabetes mellitus (GDM) has been reported to be increasing worldwide in correlation with ethnic and geographic variations. The actual prevalence of GDM throughout all of Greenland remains unknown. Objective. The aim of this study...

  5. The Braconidae (Hymenoptera) of Greenland

    NARCIS (Netherlands)

    Achterberg, van C.

    2006-01-01

    Thirty species belonging to 16 genera of the family Braconidae (Hymenoptera) are reported from Greenland. Seven are new species described and illustrated below: Dacnusa groenlandica spec. nov.; Aphidius tarsalis spec. nov.; Praon brevistigma spec. nov.; Blacus (B.) groenlandicus spec. nov.; Cotesia

  6. The Pedagogical Situation in Greenland.

    Science.gov (United States)

    Gunther, Bent

    The history of Greenland's educational activities began in 1721 with the work of a missionary who encouraged the people to learn to read and write. A century later, higher education became available. In 1905, legislation was enacted that served as a milestone of progress for the growth of education. Separation from Denmark, which was leading…

  7. Crustal structure beneath Eastern Greenland

    DEFF Research Database (Denmark)

    Reiche, Sönke; Thybo, H.; Kaip, G.

    2011-01-01

    these mountain belts is needed for assessing the isostatic balance of the crust and to gain insight into possible links between crustal composition, rifting history and present-day topography of the North Atlantic Region. However, the acquisition of geophysical data onshore Greenland is logistically complicated...

  8. Gestational diabetes mellitus in Greenland

    DEFF Research Database (Denmark)

    Pedersen, Michael Lynge; Olesen, Jesper; Jørgensen, Marit Eika

    2016-01-01

    BACKGROUND: Within the last 20 years, the prevalence of gestational diabetes mellitus (GDM) has been reported to be increasing worldwide in correlation with ethnic and geographic variations. The actual prevalence of GDM throughout all of Greenland remains unknown. OBJECTIVE: The aim of this study...

  9. Interglacial insects and their possible survival in Greenland during the last glacial stage

    DEFF Research Database (Denmark)

    Bøcher, Jens Jensenius

    2012-01-01

    Sediments from the last interglacial (Eemian) in Jameson Land, East Greenland, and the Thule area, NW Greenland, have revealed a number of insect fragments of both arctic and more or less warmth-demanding species. Altogether, the interglacial fauna of Coleoptera (beetles) indicates boreal...... beetle species such as Amara alpina and Isochnus arcticus did not survive the last glacial stage in Greenland. Two factors that have not been sufficiently considered when discussing survival contra extinction are the importance of microclimate and the number of sun-hours during the Arctic summer. Even...... among the Coleoptera, which as a group fares quite badly in the Arctic, there might be survivors, at least among those found both during the interglacial and as fossils during the early Holocene. First of all, glacial survival applies to the seed bug Nysius groenlandicus, which was widespread during...

  10. Temporal Trends and Future Predictions of Mercury Concentrations in Northwest Greenland Polar Bear (Ursus maritimus) Hair

    DEFF Research Database (Denmark)

    Dietz, Rune; Born, E.W.; Riget, Frank Farsø

    2011-01-01

    Hair samples from 117 Northwest Greenland polar bears (Ursus maritimus) were taken during 1892-2008 and analyzed for total mercury (hereafterHg). The sample represented 28 independent years and the aim of the study was to analyze for temporal Hg trends. Mercury concentrations showed yearly...... significant increases of 1.6-1.7% (p bear......-2008 concentrations ofHg in Northwest Greenland polar bear hair exceeded the general guideline values of 20-30 μg/g dry weight for terrestrial wildlife, whereas the neurochemical effect level of 5.4 μg Hg/g dry weight proposed for East Greenland polar bears was exceeded in 93.5% of the cases. These results call...

  11. Rapid response of Helheim Glacier in Greenland to climate variability over the past century

    DEFF Research Database (Denmark)

    Andresen, Camilla Snowman; Straneo, Fiammetta; Ribergaard, Mads Hvid;

    2012-01-01

    During the early 2000s the Greenland Ice Sheet experienced the largest ice-mass loss of the instrumental record(1), largely as a result of the acceleration, thinning and retreat of large outlet glaciers in West and southeast Greenland(2-5). The quasi-simultaneous change in the glaciers suggests...... a common climate forcing. Increasing air(6) and ocean(7,8) temperatures have been indicated as potential triggers. Here, we present a record of calving activity of Helheim Glacier, East Greenland, that extends back to about AD 1890, based on an analysis of sedimentary deposits from Sermilik Fjord, where...... Helheim Glacier terminates. Specifically, we use the annual deposition of sand grains as a proxy for iceberg discharge. Our record reveals large fluctuations in calving rates, but the present high rate was reproduced only in the 1930s. A comparison with climate indices indicates that high calving activity...

  12. Paleoceanographical development off Sisimiut, West Greenland, during the mid- and late Holocene. A multiproxy study

    DEFF Research Database (Denmark)

    Erbs-Hansen, D.R.; Knudsen, K.L.; Olsen, Jesper

    2013-01-01

    A multiproxy study of paleoceanographic and climatic changes in Holsteinsborg Dyb on the West Greenland shelf shows that the area is sensitive to variations in the mixing between the two components of the West Greenland Current, i.e., the Atlantic Water of the Irminger Current and the Polar Water...... from the East Greenland Current. A seismic profile illustrates the general development in the area since the deglaciation, and analyses of benthic foraminifera, stable isotopes (δ18O and δ13C), and X-ray fluorescence elemental counts in two cores, covering ca. 6650 and 1100years, respectively, provide...... details on the oceanographic changes during the mid- and late Holocene. The chronology is based on 210Pb and AMS 14C age determinations. During the time interval of 6650-1600cal.yr BP, the bottom waters are characterized by the presence of modified Atlantic Water, with some influence of meltwater, either...

  13. Magmatic Diversity of the Wehrlitic Intrusions in the Oceanic Lower Crust of the Northern Oman Ophiolite

    Science.gov (United States)

    Kaneko, R.; Adachi, Y.; Miyashita, S.

    2014-12-01

    The Oman ophiolite extends along the east coast of Oman, and is the world's largest and best-preserved slice of obducted oceanic lithosphere. The magmatic history of this ophiolite is complex and is generally regarded as having occurred in three stages (MOR magmatism, subduction magmatism and intraplate magmatism). Wehrlitic intrusions constitute an important element of oceanic lower crust of the ophiolite, and numerous intrusions cut gabbro units in the northern Salahi block of this ophiolite. In this study area, we identified two different types of wehrlitic intrusions. One type of the intrusions mainly consists of dunite, plagioclase (Pl) wehrlite and mela-olivine (Ol) gabbro, in which the crystallization sequence is Ol followed by the contemporaneous crystallization of Pl and clinopyroxene (Cpx). This type is called "ordinary" wehrlitic intrusions and has similar mineral compositions to host gabbros (Adachi and Miyashita 2003; Kaneko et al. 2014). Another type of the intrusions is a single intrusion that crops out in an area 250 m × 150 m along Wadi Salahi. This intrusion consists of Pl-free "true" wehrlite, in which the crystallization sequence is Ol and then Cpx. The forsterite contents (Fo%) of Ol from the "ordinary" wehrlitic intrusions and "true" wehrlitic intrusions have ranges of 90.8-87.0 (NiO = 0.36-0.13 wt%) and 84.7 (NiO = 0.31 wt%), respectively. Cr numbers (Cr#) of Cr-spinel from the "true" wehrlitic intrusions show higher Cr# value of 0.85 than those of the "ordinary" wehrlitic intrusions (0.48-0.64). But the former is characterized by very high Fe3+ values (YFe3+ = 0.49-0.68). Kaneko et al. (2014) showed that the "ordinary" ubiquitous type has similar features to MOR magmatism and the depleted type in the Fizh block (Adachi and Miyashita 2003) links to subduction magmatism. These types are distinguished by their mineral chemistries (TiO2 and Na2O contents of Cpx). The TiO2 and Na2O contents of Cpx from the "true" wehrlitic intrusions have 0

  14. Experimental constraints on mineral-melt reactions in the Middle Zone of the Skaergaard intrusion

    Science.gov (United States)

    Veksler, I. V.; Nielsen, T. F.

    2009-12-01

    The Eocene Skaergaard intrusion (East Greenland) is the classical example of the Fe enrichment trend in tholeitic magma. Despite numerous attempts to reproduce the trend experimentally, its direction in the Middle Zone (MZ) of the intrusion remains contentious. It remains unclear whether the strong Fe enrichment of the magma continued after the start of ilmenite and magnetite crystallization. Thy et al. (2009) recently showed that the modal ratio of Fe-Ti oxide minerals to Fe-Mg silicates in average Skaergaard rocks was lower than the experimentally determined cotectic proportions. In our view, the difference probably resulted from mineral-melt post-cumulus reactions. Cumulus assemblage in the MZ comprised plagioclase, high- and low-Ca pyroxenes, ilmenite and magnetite. Olivine is locally present as an inter-cumulus phase. All the minerals and the liquid were involved in continuous and discontinuous reaction series. Traces of the reactions are ubiquitous throughout the intrusion, and especially prominent around autolithic blocks (Irvine et al., 1998; McBirney, 2009). We examined experimental constraints on the reactions from 67 experimental equilibria compiled from 25 publications, in which dry silicate melts coexisted with plagioclase, olivine, and two pyroxenes. The experiments had been carried out at 1 atm, temperatures between 1040 and 1180 °C, and variable fO2. We found that the 4-mineral assemblage did not constrain a narrow range of liquid compositions. For example, SiO2 in the liquids varies broadly from 42 to 66 wt.%. Cotectic proportions of the crystal phases vary accordingly. FeO and alkalis impose strong and opposite effects on the cotectic proportions and equilibrium melt compositions. Thus, alkali-poor liquids evolve to FeO concentrations of up to 30 wt. %. We propose that the mineral-melt reactions compounded by migration of FeO and alkalis in the liquid may explain poorly understood phenomena such as the reverse evolution of plagioclase towards

  15. An evaluation of teeth of ringed seals (Phoca hispida) from Greenland as a matrix to monitor spatial and temporal trends of mercury and stable isotopes

    DEFF Research Database (Denmark)

    Aubail, Aurore; Dietz, Rune; Riget, Frank Farsø;

    2010-01-01

    central West Greenland and central East Greenland. These increases were attributed to global changes in environmental Hg levels since no temporal trends in δ15N values were found to support the hypothesis of a diet shift over time. Furthermore, a decreasing temporal trend in δ13C values was observed...... in the teeth of seals from central East Greenland, and explained by a likely change over time towards more pelagic feeding habits; alternatively, the so-known Seuss effect was thought to be responsible for this decrease. Finally, it was concluded that the tooth of ringed seal was a good monitoring tissue...

  16. Time trend by region of suicides and suicidal thoughts among Greenland Inuit.

    Science.gov (United States)

    Bjerregaard, Peter; Larsen, Christina Viskum Lytken

    2015-01-01

    Suicides remain a major public health problem in Greenland. Their increase coincides with the modernization since 1950. Serious suicidal thoughts are reported by a significant proportion of participants in countrywide surveys. To analyze the time trend by region of suicides and suicidal thoughts among the Inuit in Greenland. Data included the Greenland registry of causes of death for 1970-2011 and 2 cross-sectional health surveys carried out in 1993-1994 and 2005-2010 with 1,580 and 3,102 Inuit participants, respectively. Suicide rates were higher among men than women while the prevalence of suicidal thoughts was higher among women. Suicide rates for men and women together increased from 1960 to 1980 and have remained around 100 per 100,000 person-years since then. The regional pattern of time trend for suicide rates varied with an early peak in the capital, a continued increase to very high rates in remote East and North Greenland and a slow increase in villages relative to towns on the West Coast. Suicidal thoughts followed the regional pattern for completed suicides. Especially for women there was a noticeable increasing trend in the villages. The relative risk for suicide was highest among those who reported suicidal thoughts, but most suicides happened outside this high-risk group. Suicide rates and the prevalence of suicidal thoughts remain high in Greenland but different regional trends point towards an increased marginalization between towns on the central West Coast, villages and East and North Greenland. Different temporal patterns call for different regional strategies of prevention.

  17. INTERPRETATIONS OF COMPLICATED FOLDED STRUCTURES AT THE LOWER PARTS OF ANTARCTIC AND GREENLAND ICE SHEETS

    Directory of Open Access Journals (Sweden)

    Alexey N. Markov

    2015-01-01

    Full Text Available Complicated folded structures were recently recorded by radar survey in the lower portions of the Antarctic and Greenland ice sheets. From a geological point of view the Antarctic and Greenland ice sheets are considered as geological features, while the ice is classified as sedimentary or metamorphic rock. In this regard the genesis of the ice sheets is analyzed from the perspective of geodynamics and metamorphism, and complicated folded structures on radar profiles are interpreted as tectonic and metamorphic structures. This study considers the processes of three kinds of tectonic structures: glacial diapirs, glacial diapir folds and glacial intrusions. Radar profiles not only capture ice flow structure but can also detect the thermobaric field in ice sheet, and in this case the complicated folded structures are interpreted as representative of recorded metastable boundaries of ice recrystallization.

  18. An evaluation of teeth of ringed seals (Phoca hispida) from Greenland as a matrix to monitor spatial and temporal trends of mercury and stable isotopes.

    OpenAIRE

    Aubail, Aurore; Dietz, Rune; Rigét, Frank; Simon-Bouhet, Benoit; Caurant, Florence

    2010-01-01

    International audience; Total mercury (Hg) concentrations were measured in teeth of ringed seals from Qeqertarsuaq, central West Greenland (1982 to 2006) and Ittoqqortoormiit, central East Greenland (1986 to 2006). Stable isotopic ratios of carbon (13C/12C) and nitrogen (15N/14N) were determined as well to provide insights into diet variations between regions or through time. Mercury concentrations decreased the first years of life of the animals suggesting that Hg had been transferred from t...

  19. Sea ice studies in the Spitsbergen-Greenland area

    Science.gov (United States)

    Vinje, T. E. (Principal Investigator)

    1976-01-01

    The author has identified the following significant results. Detailed information on the outflow through the Fram Strait of ice from the Polar Ocean over shorter periods was obtained. It is found that the speed of the outflow may vary about 100% over periods of a few days. The core of the East Greenland Current is found between 2 deg E and 4 deg W. The speed of the surface water at 81 deg N is for a calm period estimated to be about 10 cm/s. A new surging glacier was discovered and new fronts of several glaciers were determined. The variation of the snow line with respect to distance from the coast was for the first time determined for the southern part of Spitsbergen. Great variations were observed, from 200 m in east to 550 m in the central area of the island.

  20. Greenland ice sheet initiation and Arctic sea ice coincide with Eocene and Oligocene CO2 changes

    Science.gov (United States)

    Tripati, Aradhna; Darby, Dennis

    2016-04-01

    Earth's modern ocean-climate system is largely defined by the presence of glacial ice on landmasses in both hemispheres. Northern Hemisphere ice was previously thought to have formed no earlier than the Miocene or Oligocene, about 20-30 million years after the widespread onset of Antarctic glaciation at the Eocene-Oligocene boundary. Controversially, the episodic presence of seasonal Arctic sea ice and glacial ice in the Northern Hemisphere beginning in the early Oligocene to Middle Eocene has been inferred from multiple observations. Here we use precise source determinations based on geochemical measurements of ice-rafted debris (IRD) from an ODP core in the Greenland Sea (75° N) to constrain glacial ice and sea ice-rafting in the Northern Hemisphere during the middle Eocene through early Oligocene. The chemical fingerprint of 2,334 detrital Fe oxide grains indicates most of these grains are from Greenland with >98% certainty. Thus the coarse IRD in the Greenland Sea originates from widespread areas of east Greenland as far south as the Denmark Strait area (~68° N), with additional IRD sources from the circum-Arctic Ocean. This is the first definitive evidence that mid-Eocene IRD in the Greenland Sea is from Greenland. Episodic glaciation of different source regions on Greenland is synchronous with times of ice-rafting in the western Arctic and ephemeral perennial Arctic ice cover. Intervals of bipolar glacial ice storage in the middle Eocene through early Oligocene coincide with evidence for periods of reduced CO2, associated with carbon cycle perturbations.

  1. Intrusion Detection using unsupervised learning

    Directory of Open Access Journals (Sweden)

    Kusum bharti

    2010-08-01

    Full Text Available Clustering is the one of the efficient datamining techniques for intrusion detection. In clustering algorithm kmean clustering is widely used for intrusion detection. Because it gives efficient results incase of huge datasets. But sometime kmean clustering fails to give best result because of class dominance problem and no class problem. So for removing these problems we are proposing two new algorithms for cluster to class assignment. According to our experimental results the proposed algorithm are having high precision and recall for low class instances.

  2. Building Intrusion Tolerant Software System

    Institute of Scientific and Technical Information of China (English)

    PENG Wen-ling; WANG Li-na; ZHANG Huan-guo; CHEN Wei

    2005-01-01

    In this paper, we describe and analyze the hypothesis about intrusion tolerance software system, so that it can provide an intended server capability and deal with the impacts caused by the intruder exploiting the inherent security vulnerabilities. We present some intrusion tolerance technology by exploiting N-version module threshold method in constructing multilevel secure software architecture, by detecting with hash value, by placing an "antigen" word next to the return address on the stack that is similar to human immune system, and by adding "Honey code" nonfunctional code to disturb intruder, so that the security and the availability of the software system are ensured.

  3. High-resolution Moho model for Greenland from EIGEN-6C4 gravity data

    DEFF Research Database (Denmark)

    Steffen, Rebekka; Strykowski, Gabriel; Lund, Björn

    2017-01-01

    are difficult to obtain. Here, we take advantage of the global gravity model EIGEN-6C4, together with the Parker-Oldenburg algorithm, to estimate the depth to the Moho beneath Greenland and surroundings. The available free-air gravity data are corrected for the topographic effect and the effect of sedimentary...... basins. We also correct for the effect on gravity due to the weight of the ice sheet and the accompanying deflection of the Earth's surface, which has not previously been taken into account in gravity studies of currently glaciated regions. Our final Moho depth model for Greenland has an associated...... uncertainty of ±4.5 km for areas with sedimentary basins and ±4 km for areas without sedimentary basins. The model shows maximum Moho depths below east Greenland of up to 55 km and values less than 20 km offshore east Greenland. There is a marked increase in Moho depth of 10–15 km from northern to central...

  4. A software tool for network intrusion detection

    CSIR Research Space (South Africa)

    Van der Walt, C

    2012-10-01

    Full Text Available This presentation illustrates how a recently developed software tool enables operators to easily monitor a network and detect intrusions without requiring expert knowledge of network intrusion detections....

  5. Non-Intrusive Appliance Recognition

    NARCIS (Netherlands)

    Hoogsteen, G; Hoogsteen, Gerwin; Krist, J.O.; Bakker, Vincent; Smit, Gerardus Johannes Maria

    2012-01-01

    Energy conservation becomes more important nowadays. The use of smart meters and, in the near future, smart appliances, are the key to achieve reduction in energy consumption. This research proposes a non-intrusive appliance monitor and recognition system for implementation on an embedded system. Th

  6. Occurrence of seawater intrusion overshoot

    NARCIS (Netherlands)

    Morgan, L.K.; Bakker, M.; Werner, A.D.

    2015-01-01

    A number of numerical modeling studies of transient sea level rise (SLR) and seawater intrusion (SI) in flux-controlled aquifer systems have reported an overshoot phenomenon, whereby the freshwater-saltwater interface temporarily extends further inland than the eventual steady state position. Recent

  7. Final OSWER Vapor Intrusion Guidance

    Science.gov (United States)

    EPA is preparing to finalize its guidance on assessing and addressing vapor intrusion, which is defined as migration of volatile constituents from contaminated media in the subsurface (soil or groundwater) into the indoor environment. In November 2002, EPA issued draft guidance o...

  8. Experiences with network intrusion detection

    NARCIS (Netherlands)

    Coolen, R.; Luiijf, H.A.M.; Geloven, W.J.F. van; Bakker, E.A.

    2002-01-01

    This paper describes our experience with several commercial Network Intrusion Detection Systems (NIDSs)deployed in a network connected to the Internet. Specific problems in the operation of NIDS are highlighted, and a number of solutions to identified problems will be presented. Finally, we shall pr

  9. Intrusive luxation of 60 permanent incisors

    DEFF Research Database (Denmark)

    Tsilingaridis, Georgios; Malmgren, Barbro; Andreasen, Jens O;

    2012-01-01

    Intrusive luxation in the permanent dentition is an uncommon injury but it is considered one of the most severe types of dental trauma because of the risk for damage to the periodontal ligament, pulp and alveolar bone. Management of intrusive luxation in the permanent dentition is controversial....... The purpose of this study was to evaluate pulp survival and periodontal healing in intrusive luxated permanent teeth in relation to treatment alternatives, degree of intrusion and root development....

  10. Permafrost degradation in West Greenland

    DEFF Research Database (Denmark)

    Foged, Niels Nielsen; Ingeman-Nielsen, Thomas

    2012-01-01

    Important aspects of civil engineering in West Greenland relate to the presence of permafrost and mapping of the annual and future changes in the active layer due to the ongoing climatically changes in the Arctic. The Arctic Technology Centre (ARTEK) has worked more than 10 years on this topic......, Kangerlussuaq, Sisimiut and Nuuk. They are situated in continuous, discontinuous and sporadic permafrost zones. We will show examples of detoriation of permafrost related to present local scale climate observations and large scale climate and permafrost simulations modeled numerically with the GIPL model driven...... by HIRHAM climate projections for Greenland up to 2075. The engineering modelling is based on a risk assessment methodology based on a flow diagram which classify the risk of permafrost degradation causing settlement and stability problems for buildings and infrastructures based on relatively simple...

  11. Shrub expansion in SW Greenland

    DEFF Research Database (Denmark)

    Jørgensen, Rasmus Halfdan

    to increasing shrub cover. Despite this, there is only limited experimental evidence that growth of the species responds to warming. Plant populations in fragmented and isolated locations could face problems adapting to a warming climate due to limited genetic variation and restricted migration from southern...... of firewood collection. A delayed reaction to the ending of the little ice age cannot be excluded, but seems rather unlikely considering other studies from Greenland. Effects of global warming in SW Greenland must be studied over even longer time periods than the 120 years of the current study. To answer......Arctic regions have experienced higher temperatures in recent decades, and the warming trend is projected to continue in the coming years. Arctic ecosystems are considered to be particularly vulnerable to climate change. Expansion of shrubs has been observed widely in tundra areas across the Arctic...

  12. The influence of winter and summer atmospheric circulation on the variability of temperature and sea ice around Greenland

    Directory of Open Access Journals (Sweden)

    Masayo Ogi

    2016-10-01

    Full Text Available Most peripheral seas of the Arctic Ocean have seen a pronounced rise in sea surface temperatures in the past century, and this signature of Arctic amplification in proximity to the land suggests that the observed marine and terrestrial changes might be connected to each other. Using in situ observations of temperature from nine coastal meteorological stations around Greenland (GrSTs and remotely sensed fields of sea ice extent (SIE, we examine the interannual variations of surface air temperature (T2m and sea level pressure (SLP anomalies associated with the GrSTs and SIEs surrounding Greenland, specifically within Baffin Bay, the Greenland Sea and Kara-Barents Seas. During winter, the interannual variation in T2m and SLP of the west and south coasts of GrSTs and the Baffin Bay SIE are different from that of the east coast of GrSTs and the SIEs in the Greenland Sea and Kara-Barents Seas. The GrSTs on the west and south coasts of Greenland and the Baffin Bay SIE are associated with the T2m anomalies over Baffin Bay and Davis Strait. The winter SLP patterns associated with these GrSTs and SIEs show positive anomalies over the Arctic and negative anomalies over the North Atlantic with a large-scale atmospheric circulation such as the winter NAO. On the contrary, the east coast of GrSTs and the SIEs in the Greenland Sea and Kara-Barents Seas are correlated with the T2m anomalies over the Greenland Sea and Barents Sea. The surface wind pattern associated with the SIEs in the Greenland Sea and Kara-Barents Seas has a cyclonic circulation in the Greenland Sea and Barents Sea. At the local scale the cyclonic circulation could induce negative SIE anomalies and contribute to increasing open water in the Greenland Sea and Barents Sea. The effect of the loss of sea ice and the heat from the open ocean warming to the atmosphere may influence the GrSTs in the east coast of Greenland. As a result, the T2m pattern associated with the GrSTs in the east coast of

  13. Upper mantle and crustal structure of the East Greenland Caledonides

    DEFF Research Database (Denmark)

    Schiffer, Christian; Balling, N.; Jacobsen, B. H.;

    of the North Atlantic passive margins, including the gravitational collapse, extension, rifting and a possible influence by volcanism related to the Iceland hot spot. The landscape and topography were finally shaped by extensive erosion, finding its peak in the quaternary glaciations. Seismological data were...

  14. The Neoproterozoic Tillite Group from Ella Ø, East Greenland

    DEFF Research Database (Denmark)

    Buchardt, Bjørn; Kristiansen, Kasper K.; Houmark-Nielsen, Michael

    is ~1200 m. The Ulvesø Fm rests conformably on shales and stromatolithic calcareous rocks of suggested warm water origin, and the Storeelv Fm is conformably overlain by clastic rocks showing pseudomorphoses after halite in the uppermost unit. The two diamictitic units are separated by the ~250 m thick Area...... is disconformably overlain by sediments of Cambrian age. Fieldwork by us on Ella Ø has questioned the glacial origin of at least the lower diamictitic unit (Ulvesø Fm), while the upper unit (Storeelv Fm) shows unequivocal evidence of glacial activities at the base. On Ella Ø, the thickness of the Tillite Group...... compositions of the stromatolithic carbonates of Bed Group 18 are significantly enriched compared to modern values with a mean of +7‰ V-PDB. The shift from calcareous rocks of Bed Group 18 to shaly and cherty sediments of Bed Group 19 is accompanied by a negative shift in d13C of more that 15‰, and average...

  15. Homicide in Greenland 1985-2010

    DEFF Research Database (Denmark)

    Christensen, Martin R; Thomsen, Asser Hedegård; Høyer, Christian Bjerre;

    2016-01-01

    PURPOSE: Homicide in Greenland has not often been investigated. The latest published study documented a dramatic rise in the homicide rate from around 1/100,000 inhabitants to more than 23/100,000 inhabitants from 1946 to 1984. The aim of our study was to characterize homicides in Greenland from ...

  16. Lead sources in human diet in Greenland

    DEFF Research Database (Denmark)

    Bjerregaard, Peter; Johansen, Poul; Mulvad, Gert

    2004-01-01

    Although blood lead levels have declined in Greenland, they are still elevated despite the fact that lead levels in the Greenland environment are very low. Fragments of lead shot in game birds have been suggested as an important source of dietary exposure, and meals of sea birds, particularly eid...

  17. Record Summer Melt in Greenland in 2010

    NARCIS (Netherlands)

    Tedesco, M.; Fettweis, X.; van den Broeke, M.R.; van de Wal, R.S.W.; Smeets, C.J.P.P.; van de Berg, W.J.; Serreze, M.C.; Box, J.E.

    2011-01-01

    As Arctic temperatures increase, there is growing concern about the melting of the Greenland ice sheet, which reached a new record during the summer of 2010. Understanding the changing surface mass balance of the Greenland ice sheet requires appreciation of the close links among changes in surface a

  18. Clouds enhance Greenland ice sheet meltwater runoff

    NARCIS (Netherlands)

    Van Tricht, K.; Lhermitte, S.; Lenaerts, J. T M|info:eu-repo/dai/nl/314850163; Gorodetskaya, I. V.; L'Ecuyer, T. S.; Noël, B.|info:eu-repo/dai/nl/370612345; Van Den Broeke, M. R.|info:eu-repo/dai/nl/073765643; Turner, D. D.; Van Lipzig, N. P M

    2016-01-01

    The Greenland ice sheet has become one of the main contributors to global sea level rise, predominantly through increased meltwater runoff. The main drivers of Greenland ice sheet runoff, however, remain poorly understood. Here we show that clouds enhance meltwater runoff by about one-third relative

  19. Balance velocities of the Greenland ice sheet

    DEFF Research Database (Denmark)

    Joughin, I.; Fahnestock, M.; Ekholm, Simon;

    1997-01-01

    We present a map of balance velocities for the Greenland ice sheet. The resolution of the underlying DEM, which was derived primarily from radar altimetery data, yields far greater detail than earlier balance velocity estimates for Greenland. The velocity contours reveal in striking detail......, the balance map is useful for ice-sheet modelling, mass balance studies, and field planning....

  20. Clouds enhance Greenland ice sheet meltwater runoff

    NARCIS (Netherlands)

    Van Tricht, K.; Lhermitte, S.; Lenaerts, J. T M|info:eu-repo/dai/nl/314850163; Gorodetskaya, I. V.; L'Ecuyer, T. S.; Noël, B.|info:eu-repo/dai/nl/370612345; Van Den Broeke, M. R.|info:eu-repo/dai/nl/073765643; Turner, D. D.; Van Lipzig, N. P M

    2016-01-01

    The Greenland ice sheet has become one of the main contributors to global sea level rise, predominantly through increased meltwater runoff. The main drivers of Greenland ice sheet runoff, however, remain poorly understood. Here we show that clouds enhance meltwater runoff by about one-third relative

  1. The Greenland Analogue Project. Yearly Report 2009

    Energy Technology Data Exchange (ETDEWEB)

    2010-12-15

    A deep geological repository for spent nuclear fuel needs to be designed to keep used nuclear fuel isolated from mankind and the environment for a million years. Within this time frame glacial conditions are expected in regions that have been glaciated in the past two to ten million years. Climate induced changes such as the growth of ice sheets and permafrost will influence and alter the ground surface and subsurface environment, including its hydrology, which may impact repository safety. Glaciation impact assessments have to-date used over-simplified models and conservative assumptions, for example in the representation of ice sheet hydrology, that do not reflect the complexity of natural systems and processes. This is largely due to lack of direct observations of such processes from existing ice sheets, which if more readily available could help reduce uncertainties and provide a strong scientific basis for the treatment of glacial impacts in safety assessments. Our current understanding of the hydrological, hydrogeological and hydrogeochemical processes associated with glacial cycles and their impact on the long-term performance of deep geological repositories for spent nuclear fuel will be significantly improved by studying a modern analogue. To advance the understanding of processes associated with glaciation and their impact on the long-term performance of a deep geological repository, the Greenland Analogue Project (GAP), a four-year field and modelling study of the Greenland ice sheet and sub-surface conditions, has been initiated collaboratively by SKB, Posiva and NWMO. The study site encompasses a land terminus portion of the Greenland ice sheet east of Kangerlussuaq and is in many ways considered to be an appropriate analogue of the conditions that are expected to prevail in much of Canada and Fennoscandia during future glacial cycles. The project is planned to run from 2009 until 2012. The GAP will conduct the first in situ investigations of some of

  2. Zircon Recycling in Arc Intrusions

    Science.gov (United States)

    Miller, J.; Barth, A.; Matzel, J.; Wooden, J.; Burgess, S.

    2008-12-01

    Recycling of zircon has been well established in arc intrusions and arc volcanoes, but a better understanding of where and how zircons are recycled can help illuminate how arc magma systems are constructed. To that end, we are conducting age, trace element (including Ti-in-zircon temperatures; TzrnTi) and isotopic studies of zircons from the Late Cretaceous (95-85 Ma) Tuolumne Intrusive Suite (TIS) in the Sierra Nevada Batholith (CA). Within the TIS zircons inherited from ancient basement sources and/or distinctly older host rocks are uncommon, but recycled zircon antecrysts from earlier periods of TIS-related magmatism are common and conspicuous in the inner and two most voluminous units of the TIS, the Half Dome and Cathedral Peak Granodiorites. All TIS units have low bulk Zr ([Zr]825°C), [Zr] in the TIS is a factor of 2 to 3 lower than saturation values. Low [Zr] in TIS rocks might be attributed to a very limited supply of zircon in the source, by disequilibrium melting and rapid melt extraction [1], by melting reactions involving formation of other phases that can incorporate appreciable Zr [2], or by removal of zircon at an earlier stage of magma evolution. Based on a preliminary compilation of literature data, low [Zr] is common to Late Cretaceous N.A. Cordilleran granodioritic/tonalitic intrusions (typically Tzrnsat [3]. A corollary is that slightly older zircon antecrysts that are common in the inner units of the TIS could be considered inherited if they are derived from remelting of slightly older intrusions. Remelting at such low temperatures in the arc would require a source of external water. Refs: [1] Sawyer, J.Pet 32:701-738; [2] Fraser et al, Geology 25:607-610; [3] Harrison et al, Geology 35:635- 638

  3. Active predation by Greenland shark Somniosus microcephalus

    DEFF Research Database (Denmark)

    Nielsen, Julius; hedeholm, Rasmus; Simon, Malene

    2013-01-01

    Dansk Havforskermøde 2013 Julius Nielsen, Rasmus Hedeholm, Malene Simon og John Fleng Steffensen The Greenland shark is ubiquitous in the northern part of the North Atlantic ranging from eastern Canada to northwest Russia . Although knowledge is scarce it is believed to be abundant and potentially...... important part of the ecosystem. Whether Greenland sharks in general should be considered opportunistic scavengers or active predators is therefore important in understanding ecosystem dynamics. Due to its sluggish appearance and a maximum reported swimming speed of 74 cm per second scavenging seems...... the most likely feeding strategy. However, recent studies suggest that Greenland sharks in some areas feed actively upon seals . Feeding ecology is poorly described in Greenland waters. In this study we provide information on feeding habits of 29 sharks caught in Greenland waters in the summer 2012...

  4. Greenland temperature response to climate forcing during the last deglaciation

    Science.gov (United States)

    Buizert, C.; Gkinis, V.; Severinghaus, J. P.; He, F.; Lecavalier, B.; Kindler, P.; Leuenberger, M.; Carlson, A. E.; Vinther, B.; White, J. W.; Liu, Z.; Otto-Bliesner, B. L.; Brook, E.

    2013-12-01

    Much of the regional and global climate variability during the last glacial termination (19-11 ka BP) can be explained as the superposition of two distinct modes (1, 2); a spatially uniform increase in global temperature correlated with greenhouse gas forcing, and a redistribution of heat associated with variability in the Atlantic meridional overturning circulation (AMOC) strength. The latter mode is expressed most clearly in the abrupt climate shifts recorded in the precipitation isotopic composition (δ18O) of Greenland ice cores, which are now widely used as a template for abrupt change in the northern hemisphere. Greenland δ18O is influenced by many factors, including source temperature, moisture transport and origin, and precipitation seasonality, complicating reconstruction of past temperatures. Here we use three non-δ18O temperature reconstructions from three ice cores and a general circulation model (GCM) to elucidate the (often abrupt) Greenland surface temperature response to external (insolation) and internal (CO2, AMOC, ice topography) climate forcings during the last termination. Our reconstructions are based on δ15N (NEEM, GISP2) and water isotope diffusion (NGRIP), both of which depend on physical processes in the firn column. The GCM and our reconstructions show excellent agreement on several key features. First, we find that the Younger Dryas (YD) period was 4-6oC warmer than the Oldest Dryas (OD) period in response to increased summer insolation and CO2 forcing. By contrast, δ18O-based reconstrucions from Greenland summit suggest the YD to be the colder of the two periods. Our finding is consistent with non-ice core NH proxy reconstructions, as well as with East Greenland deglacial moraine sequences that suggest only a modest glacial re-advance during the YD. Second, the YD-OD temperature difference shows a polar amplification signal, with warming being greatest at the northernmost NEEM site. By isolating different forcings in the GCM, we

  5. Timing of the Little Ice Age in southern Greenland

    Science.gov (United States)

    Kjær, Kurt H.; Kjeldsen, Kristian K.; Bjørk, Anders A.; Khan, Shfaqat A.; Korsgaard, Niels J.; Funder, Svend; Larsen, Nicolaj K.; Vinther, Bo; Andresen, Camilla S.; Long, Antony J.; Woodroffe, Sarah A.; Steen Hansen, Eric; Olsen, Jesper

    2013-04-01

    Northern hemisphere temperatures reached their Holocene minimum and most glaciers reached their maximum during The Little Ice Age (LIA), but the timing of specific cold intervals is site-specific. In southern Greenland, we have compiled data from organic matter incorporated in LIA sediments, used as a signal for ice-free terrain being overridden by LIA glacier advances, and data from threshold lakes showing the onset of glacier-fed lakes, thus revealing the advance-maximum phase initiating the LIA. Finally, we have compiled lichenometry results indicating the onset of bedrock vegetation succeeding ice retreat. Our results show that the advance of glaciers during the LIA occurs early after the Medieval Warm Period terminating soon after 1200 AD and culminates c. 1500-1600 AD. Historical maps also show that many glaciers on the western coast occupy a still-stand near the LIA maximum until 1900 AD before retreat commence. Thus in southern Greenland, we define LIA as the period between the first signs of Late Holocene glacier readvance and the latest onset of retreat - i.e. from ca. 1200 to c. 1900. During this period northern hemisphere annual mean temperatures, although fluctuating, were generally below the 1961-1990 average, with the coldest interval between c. 1600 and 1800. Even though winter temperatures may have dominated the cooling, also the summer temperatures which are most closely correlated with glacier mass balances, dropped, to c. 0.6° below the average in the northern hemisphere including the Arctic. Furthermore, the glacier response seems to be mirrored by a oceanic cooling between 500-1000 AD, followed by onset of the LIA at 1150-1250 AD as seen in the relative strength of warm subsurface water and the influence of the East Greenland Current.

  6. Holocene climate change in Arctic Canada and Greenland

    Science.gov (United States)

    Briner, Jason P.; McKay, Nicholas P.; Axford, Yarrow; Bennike, Ole; Bradley, Raymond S.; de Vernal, Anne; Fisher, David; Francus, Pierre; Fréchette, Bianca; Gajewski, Konrad; Jennings, Anne; Kaufman, Darrell S.; Miller, Gifford; Rouston, Cody; Wagner, Bernd

    2016-09-01

    This synthesis paper summarizes published proxy climate evidence showing the spatial and temporal pattern of climate change through the Holocene in Arctic Canada and Greenland. Our synthesis includes 47 records from a recently published database of highly resolved Holocene paleoclimate time series from the Arctic (Sundqvist et al., 2014). We analyze the temperature histories represented by the database and compare them with paleoclimate and environmental information from 54 additional published records, mostly from datasets that did not fit the selection criteria for the Arctic Holocene database. Combined, we review evidence from a variety of proxy archives including glaciers (ice cores and glacial geomorphology), lake sediments, peat sequences, and coastal and deep-marine sediments. The temperature-sensitive records indicate more consistent and earlier Holocene warmth in the north and east, and a more diffuse and later Holocene thermal maximum in the south and west. Principal components analysis reveals two dominant Holocene trends, one with early Holocene warmth followed by cooling in the middle Holocene, the other with a broader period of warmth in the middle Holocene followed by cooling in the late Holocene. The temperature decrease from the warmest to the coolest portions of the Holocene is 3.0 ± 1.0 °C on average (n = 11 sites). The Greenland Ice Sheet retracted to its minimum extent between 5 and 3 ka, consistent with many sites from around Greenland depicting a switch from warm to cool conditions around that time. The spatial pattern of temperature change through the Holocene was likely driven by the decrease in northern latitude summer insolation through the Holocene, the varied influence of waning ice sheets in the early Holocene, and the variable influx of Atlantic Water into the study region.

  7. Ocean surface conditions on the SE Greenland shelf during the last millennium - from abrupt changes to centennial variability

    Science.gov (United States)

    Miettinen, Arto; Divine, Dmitry; Husum, Katrine; Koç, Nalan; Jennings, Anne

    2016-04-01

    possible. The regional influence of the Greenland ice sheet can be prominent in specific conditions, as seen during the early MCA. Because these oceanic changes can have a global impact through their potential influence on the AMOC, this highlights the importance of Greenland ice sheet and the neighboring ocean with its major surface current, the East Greenland Current, under the present warming conditions.

  8. The Greenland Ice Mapping Project

    Science.gov (United States)

    Joughin, I.; Smith, B.; Howat, I. M.; Moon, T. A.; Scambos, T. A.

    2015-12-01

    Numerous glaciers in Greenland have sped up rapidly and unpredictably during the first part of the 21st Century. We started the Greenland Ice Mapping Project (GIMP) to produce time series of ice velocity for Greenland's major outlet glaciers. We are also producing image time series to document the advance and retreat of glacier calving fronts and other changes in ice-sheet geometry (e.g., shrinking ice caps and ice shelves). When the project began, there was no digital elevation model (DEM) with sufficient accuracy and resolution to terrain-correct the SAR-derived products. Thus, we also produced the 30-m GIMP DEM, which, aside from improving our processing, is an important product in its own right. Although GIMP focuses on time series, complete spatial coverage for initializing ice sheet models also is important. There are insufficient data, however, to map the full ice sheet in any year. There is good RADARSAT coverage for many years in the north, but the C-band data decorrelate too quickly to measure velocity in the high accumulation regions of the southeast. For such regions, ALOS data usually correlate well, but speckle-tracking estimates at L-band are subject to large ionospheric artifacts. Interferometric phase data are far less sensitive to the effect of the ionosphere, but velocity estimates require results from crossing orbits. Thus, to produce a nearly complete mosaic we used data from multiple sensors, beginning with ERS-1/2 data from the mid 1990s. By using a primarily phase-only solution for much of the interior, we have reduced the velocity errors to ~1-3 m/yr. For the faster moving ice-sheet margin where phase data cannot be unwrapped, we used speckle-tracking data. In particular, we have relied on TerraSAR-X for many fast-moving glaciers because the ionosphere far less affects X-band data. This pan-Greenland velocity map as well as many of the time series would not have been possible without an extensive archive of data collected using six

  9. Reuse of harbour sediments in the Greenlandic construction industry

    DEFF Research Database (Denmark)

    Belmonte, Louise Josefine; Kirkelund, Gunvor Marie; Ottosen, Lisbeth M.

    2010-01-01

    The purpose of this study is to investigate possibilities of using harbour sediments from the Greenlandic harbours as substitutes in the Greenlandic construction industry, mainly for concrete production and road construction. Materials for use in the Greenlandic construction industry are shipped ...... to Greenland from all over the world and reuse and use of resources already in Greenland would therefore make a huge contribution to the local community....

  10. Rapid population increase in an introduced muskox population, West Greenland

    Directory of Open Access Journals (Sweden)

    Carsten Riis Olesen

    1993-10-01

    Full Text Available In 1962 and 1965, 27 (13 and 14 muskox yearlings were translocated from East Greenland (71°N to the Angujaartorfiup Nunaa range in West Greenland (67°N. Angujaartorfiup Nunaa is a 6600 km2 icefree, continental area where caribou are indigenous. The climate is strictly continental with a minimum of precipitation but with abundant vegetation. Aerial surveys in 1990 documented that the muskox population has increased to 2600 heads despite quota-based harvesting since 1988. The annual quota was 200, 300 and 400 for 1988, 1989 and 1990, respectively. Distribution of muskoxen shows a significant preference for low altitude habitats southeast of Kangerlussuaq Airport and around Arnangarnup Qoorua (Paradise valley. Annual population increment averages 30% and the calf crop is around 24% of the population. Yearling recruitment in the population reveals that calf mortality during winter is very limited. About half of the 1-year-old females are served and they eventually give birth to their first calf when they turn 2 years old. With half of the 2-year-old females reproducing, the calf/cow ration ranges between 0.9 and 1.0.

  11. Classification and Importance of Intrusion Detection System

    Directory of Open Access Journals (Sweden)

    Rajasekaran K

    2012-08-01

    Full Text Available An intrusion detection system (IDS is a device or software application that monitors network or system activities for malicious activities or policy violations and produces reports to a Management Station. Some systems may attempt to stop an intrusion attempt but this is neither required nor expected of a monitoring system. Due to a growing number of intrusion events and also because the Internet and local networks have become so ubiquitous, organizations are increasingly implementing various systems that monitor IT security breaches. This includes an overview of the classification of intrusion detection systems and introduces the reader to some fundamental concepts of IDS methodology: audit trail analysis and on-the-fly processing as well as anomaly detection and signature detection approaches. This research paper discusses the primary intrusion detection techniques and the classification of intrusion Detection system.

  12. Nearshore magnetic anomalies of inner shelf of Bhimunipatnam-Pudimadaka, east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Subrahmanyam, A.S.; Rao, K.M.; Murthy, K.S.R.; Rao, T.C.S.

    Analysis of marine magnetic data of the nearshore marine environment between Bhimunipatnam and Pudimadaka, on the East Coast of India indicate charnockite intrusions in the innershelf in certain areas. From the analysis of magnetic data...

  13. Oceanic transport of surface meltwater from the southern Greenland ice sheet

    Science.gov (United States)

    Luo, Hao; Castelao, Renato M.; Rennermalm, Asa K.; Tedesco, Marco; Bracco, Annalisa; Yager, Patricia L.; Mote, Thomas L.

    2016-07-01

    The Greenland ice sheet has undergone accelerating mass losses during recent decades. Freshwater runoff from ice melt can influence fjord circulation and dynamics and the delivery of bioavailable micronutrients to the ocean. It can also have climate implications, because stratification in the adjacent Labrador Sea may influence deep convection and the strength of the Atlantic meridional overturning circulation. Yet, the fate of the meltwater in the ocean remains unclear. Here, we use a high-resolution ocean model to show that only 1-15% of the surface meltwater runoff originating from southwest Greenland is transported westwards. In contrast, up to 50-60% of the meltwater runoff originating from southeast Greenland is transported westwards into the northern Labrador Sea, leading to significant salinity and stratification anomalies far from the coast. Doubling meltwater runoff, as predicted in future climate scenarios, results in a more-than-double increase in anomalies offshore that persists further into the winter. Interannual variability in offshore export of meltwater is tightly related to variability in wind forcing. The new insight that meltwaters originating from the west and east coasts have different fates indicates that future changes in mass loss rates and surface runoff will probably impact the ocean differently, depending on their Greenland origins.

  14. Oceanic Transport of Surface Meltwater from the Southern Greenland Ice Sheet

    Science.gov (United States)

    Luo, Hao; Castelao, Renato M.; Rennermalm, Asa K.; Tedesco, Marco; Bracco, Annalisa; Yager, Patricia L.; Mote, Thomas L.

    2016-01-01

    The Greenland ice sheet has undergone accelerating mass losses during recent decades. Freshwater runoff from ice melt can influence fjord circulation and dynamic1 and the delivery of bioavailable micronutrients to the ocean. It can also have climate implications, because stratification in the adjacent Labrador Sea may influence deep convection and the strength of the Atlantic meridional overturning circulation. Yet, the fate of the meltwater in the ocean remains unclear. Here, we use a high-resolution ocean model to show that only 1-15% of the surface meltwater runoff originating from southwest Greenland is transported westwards. In contrast, up to 50-60% of the meltwater runoff originating from southeast Greenland is transported westwards into the northern Labrador Sea, leading to significant salinity and stratification anomalies far from the coast. Doubling meltwater runoff, as predicted in future climate scenarios, results in a more-than-double increase in anomalies offshore that persists further into the winter. Interannual variability in offshore export of meltwater is tightly related to variability in wind forcing. The new insight that meltwaters originating from the west and east coasts have different fates indicates that future changes in mass loss rates and surface runoff will probably impact the ocean differently, depending on their Greenland origins.

  15. Association Rules Applied to Intrusion Detection

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    We discuss the basic intrusion detection techniques, and focus on how to apply association rules to intrusion detection. Begin with analyzing some close relations between user's behaviors, we discuss the mining algorithm of association rules and apply to detect anomaly in IDS. Moreover, according to the characteristic of intrusion detection, we optimize the mining algorithm of association rules, and use fuzzy logic to improve the system performance.

  16. Non-intrusive refractometer sensor

    Indian Academy of Sciences (India)

    Pabitra Nath

    2010-04-01

    An experimental realization of a simple non-intrusive refractometer sensor is demonstrated in this communication. The working principle of the sensor is based on intensity modulation of the back-reflected light when output light from an optical fibre end focusses onto air–medium interface. The change in the refractive index of the medium affects the reflectance of the incident light signal and thus modulates the back-reflected signal. Refractive index variation as small as 0.002 RIU can be measured using the present technique. The advantages of the technique are its simplicity, cost efficiency and usefulness in monitoring refractive indices of acidic solutions.

  17. Population Structure of West Greenland Narwhals

    DEFF Research Database (Denmark)

    Riget, F.; Dietz, R.; Møller, P.

    The hypothesis that different populations of narwhals in the West Greenland area exist has been tested by different biomarkers (metal and organochlorine concentrations, stable isotopes and DNA). Samples of muscle, liver, kidney, blubber and skin tissues of narwhals from West Greenland have been...... analysed for heavy metals, organochlorines, stable isotopes and DNA. The obtained results of metal concentrations and DNA were included in the existing database, whereas no previous data on organochlorines and stable isotopes in West Greenland narwhals existed. The metal and POP concentrations and stable...

  18. Impact of public health research in Greenland

    DEFF Research Database (Denmark)

    Bjerregaard, Peter; Curtis, Tine

    2004-01-01

    research. Two health surveys have been carried out in Greenland by the National Institute of Public Health, and a follow-up is being planned together with the Directorate of Health. The results have been widely used by politicians, administrators, and health care professionals.......In 1992, the Greenland Home Rule Government took over the responsibility for health care. There has since been a growing cooperation between the Directorate of Health and researchers in Denmark and Greenland, for instance by the Directorate supporting workshops and funding a chair in health...

  19. Destabilization of the Northeast Greenland Ice Stream

    DEFF Research Database (Denmark)

    Korsgaard, N. J.; Khan, Shfaqat Abbas; Kjaer, K. H.

    . Here, we reveal that the Northeast Greenland Ice Stream (NEGIS), which extends more than 600 km into the interior of the ice sheet, is now undergoing dynamic thinning after more than a quarter of a century of stability. This sector of the GrIS is of particular interest in sea level projections, because...... the glacier flows into a large submarine basin with a negative bed slope near the grounding line. Our findings unfold the next step in mass loss of the GrIS as we show a heightened risk of rapid sustained loss from Northeast Greenland on top of the thinning in Southeast and Northwestern Greenland....

  20. Improving the Greenlandic Greenhouse Gas Inventory

    DEFF Research Database (Denmark)

    Nielsen, Ole-Kenneth; Baunbæk, Lene; Gyldenkærne, Steen

    The project to improve the Greenlandic greenhouse gas (GHG) inventory was undertaken due to the recommendations made by the UNFCCC review team in connection with the 2008 and 2009 submissions by the Kingdom of Denmark. The improvements made to the Greenlandic GHG emission inventory were substantial...... the methodologies that had been previously used. The changes made to the Greenlandic GHG inventory as a result of this project resulted in recalculations of the GHG emission of 14.3 Gg of CO2 equivalents in 2007, which roughly corresponds to 2 % of the total GHG emissions...

  1. Sulfide intrusion and detoxification in Zostera marina

    DEFF Research Database (Denmark)

    Hasler-Sheetal, Harald; Holmer, Marianne

    2014-01-01

    nutrition in general. By a global review of sulfide intrusion, coupled with a series of field studies and in situ experiments we elucidate sulfide intrusion and different strategies of seagrasses to sustain sulfide intrusion. Using stable isotope tracing, scanning electron microscopy with x-ray analysis...... indicating a possible role of sulfide in the sulfur nutrition beside the detoxification function. Our results suggest different adaptations of Z. marina to reduced sediments and sulfide intrusion ranging from bacterial and chemical reoxidation of sulfide to sulfate to incorporation of sulfide into organic...

  2. An international perspective on Facebook intrusion.

    Science.gov (United States)

    Błachnio, Agata; Przepiorka, Aneta; Benvenuti, Martina; Cannata, Davide; Ciobanu, Adela Magdalena; Senol-Durak, Emre; Durak, Mithat; Giannakos, Michail N; Mazzoni, Elvis; Pappas, Ilias O; Popa, Camelia; Seidman, Gwendolyn; Yu, Shu; Wu, Anise M S; Ben-Ezra, Menachem

    2016-08-30

    Facebook has become one of the most popular social networking websites in the world. The main aim of the study was to present an international comparison of Facebook intrusion and Internet penetration while examining possible gender differences. The study consisted of 2589 participants from eight countries: China, Greece, Israel, Italy, Poland, Romania, Turkey, USA. Facebook intrusion and Internet penetration were taken into consideration. In this study the relationship between Facebook intrusion and Internet penetration was demonstrated. Facebook intrusion was slightly negatively related to Internet penetration in each country.

  3. Spatial and temporal oxygen isotope variability in northern Greenland - implications for a new climate record over the past millennium

    Science.gov (United States)

    Weißbach, S.; Wegner, A.; Opel, T.; Oerter, H.; Vinther, B. M.; Kipfstuhl, S.

    2016-02-01

    We present for the first time all 12 δ18O records obtained from ice cores drilled in the framework of the North Greenland Traverse (NGT) between 1993 and 1995 in northern Greenland. The cores cover an area of 680 km × 317 km, 10 % of the Greenland ice sheet. Depending on core length (100-175 m) and accumulation rate (90-200 kg m-2 a-1) the single records reflect an isotope-temperature history over the last 500-1100 years. Lowest δ18O mean values occur north of the summit and east of the main divide as a consequence of Greenland's topography. In general, ice cores drilled on the main ice divide show different results than those drilled east of the main ice divide that might be influenced by secondary regional moisture sources. A stack of all NGT records and the NGRIP record is presented with improved signal-to-noise ratio. Compared to single records, this stack represents the mean δ18O signal for northern Greenland that is interpreted as proxy for temperature. Our northern Greenland δ18O stack indicates distinctly enriched δ18O values during medieval times, about AD 1420 ± 20 and from AD 1870 onwards. The period between AD 1420 and AD 1850 has depleted δ18O values compared to the average for the entire millennium and represents the Little Ice Age. The δ18O values of the 20th century are comparable to the medieval period but are lower than that about AD 1420.

  4. Seafloor geomorphology and glacimarine sedimentation associated with fast-flowing ice sheet outlet glaciers in Disko Bay, West Greenland

    Science.gov (United States)

    Streuff, Katharina; Ó Cofaigh, Colm; Hogan, Kelly; Jennings, Anne; Lloyd, Jeremy M.; Noormets, Riko; Nielsen, Tove; Kuijpers, Antoon; Dowdeswell, Julian A.; Weinrebe, Wilhelm

    2017-08-01

    Fast-flowing outlet glaciers currently drain the Greenland Ice Sheet (GIS), delivering ice, meltwater and debris to the fjords around Greenland. Although such glaciers strongly affect the ice sheet's mass balance, their glacimarine processes and associated products are still poorly understood. This study provides a detailed analysis of lithological and geophysical data from Disko Bay and the Vaigat Strait in central West Greenland. Disko Bay is strongly influenced by Jakobshavn Isbræ, Greenland's fastest-flowing glacier, which currently drains ∼7% of the ice sheet. Streamlined glacial landforms record the former flow of an expanded Jakobshavn Isbræ and adjacent GIS outlets through Disko Bay and the Vaigat Strait towards the continental shelf. Thirteen vibrocores contain a complex set of lithofacies including diamict, stratified mud, interbedded mud and sand, and bioturbated mud deposited by (1) suspension settling from meltwater plumes and the water column, (2) sediment gravity flows, and (3) iceberg rafting and ploughing. The importance of meltwater-related processes to glacimarine sedimentation in West Greenland fjords and bays is emphasised by the abundance of mud preserved in the cores. Radiocarbon dates constrain the position of the ice margin during deglaciation, and suggest that Jakobshavn Isbræ had retreated into central Disko Bay before 10.6 cal ka BP and to beyond Isfjeldsbanken by 7.6-7.1 cal ka BP. Sediment accumulation rates were up to 1.7 cm a-1 for ice-proximal glacimarine mud, and ∼0.007-0.05 cm a-1 for overlying distal sediments. In addition to elucidating the deglacial retreat history of Jakobshavn Isbræ, our findings show that the glacimarine sedimentary processes in West Greenland are similar to those in East Greenland, and that variability in such processes is more a function of time and glacier proximity than of geographic location and associated climatic regime.

  5. Hepatitis B prevalence and incidence in Greenland

    DEFF Research Database (Denmark)

    Børresen, Malene Landbo; Andersson, Mikael; Wohlfahrt, Jan

    2015-01-01

    Greenland remains a highly endemic area for hepatitis B virus (HBV) infection. This is in sharp contrast to other modern societies, such as Denmark. To address this discrepancy, we investigated the natural history of HBV infection in Greenland by estimating the age-specific incidence of HBV...... infection, the proportion of chronic carriers, and the rates of hepatitis B surface antigen seroclearance. In total, 8,879 Greenlanders (16% of the population) from population-based surveys conducted in 1987 and 1998 were followed through March 2010. Data on HBV status were supplemented by HBV test results...... from all available HBV registries in Greenland to determine changes in HBV status over time. Incidence rates of HBV infection and hepatitis B surface antigen seroclearance were estimated after taking into account interval censoring. The incidence of HBV infection in 5-14-year-old subjects was less than...

  6. Small-scale fisheries in Greenlandic planning

    DEFF Research Database (Denmark)

    Jacobsen, Rikke Becker

    2013-01-01

    This article analyses an ongoing planning process in Greenlandic fisheries governance aiming to reform the coastal Greenland halibut fishery. It examines the way certain truths about this fishery and the need for reform are produced up to and in the final policy document ‘regulation concerning...... governmentality: The process whereby a selected fishery becomes subjected to planned out-phasing through a combined construction of fleet and human identity....... the coastal fishery for Greenland halibut’. Findings highlight the way the small-scale Greenland halibut fishery system becomes a particular governance problem with respect to particular contextual meanings of sustainability and long-term planning. The article then examines whether this governance problem...

  7. Alcohol in Greenland 1951-2010

    DEFF Research Database (Denmark)

    Aage, Hans

    2012-01-01

    Background. Fluctuations in alcohol consumption in Greenland have been extreme since alcohol became available to the Greenland Inuit in the 1950s, increasing from low levels in the 1950s to very high levels in the 1980s about twice as high as alcohol consumption in Denmark. Since then, consumption...... has declined, and current consumption is slightly below alcohol consumption in Denmark, while alcohol prices are far above Danish prices. Objective. Description of historical trends and possible causal connections of alcohol prices, alcohol consumption and alcohol-related mortality in Greenland 1951......-2010 as a background for the evaluation of the impact of various types of policy. Design. Time series for Greenland 1951-2010 for alcohol prices, consumption and mortality are compiled, and variation and correlations are discussed in relation to various policies aimed at limiting alcohol consumption. Corresponding...

  8. Trends of cervical cancer in Greenland

    DEFF Research Database (Denmark)

    Sander, Bente B; Rebolj, Matejka; Lynge, Elsebeth

    2014-01-01

    BACKGROUND: Due to its extraordinarily fast economic and social transition, virtually closed borders before 1940 and, moreover, that 85% of the population has the distinctive genetics of the Inuit, Greenland is a very interesting country to study cervical cancer from a historical perspective....... Nevertheless, little has been reported about long-term cancer trends in Greenland. Our aim was to describe and interpret the incidence of cervical cancer from 1950 to 2009. MATERIAL AND METHODS: We systematically searched PubMed for articles reporting the incidence of cervical cancer in Greenland. We...... supplemented this with data for 1980-2009 obtained from the Chief Medical Officer of Greenland. RESULTS: Incidence of cervical cancer was around 10 per 100 000 women (age-standardised, world population, ASW) in the 1950s, 30 per 100 000 in the 1960s, and in the 1980s around 60 per 100 000. From 1985 onwards...

  9. Small-scale fisheries in Greenlandic planning

    DEFF Research Database (Denmark)

    Jacobsen, Rikke Becker

    2013-01-01

    This article analyses an ongoing planning process in Greenlandic fisheries governance aiming to reform the coastal Greenland halibut fishery. It examines the way certain truths about this fishery and the need for reform are produced up to and in the final policy document ‘regulation concerning...... the coastal fishery for Greenland halibut’. Findings highlight the way the small-scale Greenland halibut fishery system becomes a particular governance problem with respect to particular contextual meanings of sustainability and long-term planning. The article then examines whether this governance problem...... could also be understood as primarily a problem to a certain ‘governmentality’ mode of governance. Whereas some fishery studies document how governmentality modes of governance in fisheries succeeds in transforming subjectivities, this study offers a view into the process that might go before successful...

  10. IceBridge BedMachine Greenland

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains bed topography beneath the Greenland Ice Sheet based on mass conservation derived from airborne radar tracks and satellite radar. The data...

  11. Land Ice: Greenland & Antarctic ice mass anomaly

    Data.gov (United States)

    National Aeronautics and Space Administration — Data from NASA's Grace satellites show that the land ice sheets in both Antarctica and Greenland are losing mass. The continent of Antarctica (left chart) has been...

  12. Greenland Radar Ice Sheet Thickness Measurements

    Data.gov (United States)

    National Aeronautics and Space Administration — Two 150-MHz coherent radar depth sounders were developed and flown over the Greenland ice sheet to obtain ice thickness measurements in support of PARCA...

  13. Developing renewable energy in discontiguous Greenland

    DEFF Research Database (Denmark)

    Carruth, Susan

    2016-01-01

    Infrastructural Urbanism’s advocacy of creating synergies between technological, economical, and ecological processes holds great potential for guiding domestic energy planning in a transforming Greenland. However, the movement has largely been conceived in the context of regional paradigms very...

  14. Intrusive and Non-Intrusive Load Monitoring (A Survey

    Directory of Open Access Journals (Sweden)

    Marco Danilo Burbano Acuña

    2015-05-01

    Full Text Available There is not discussion about the need of energyconservation, it is well known that energy resources are limitedmoreover the global energy demands will double by the end of2030, which certainly will bring implications on theenvironment and hence to all of us.Non-Intrusive load monitoring (NILM is the process ofrecognize electrical devices and its energy consumption basedon whole home electric signals, where this aggregated load datais acquired from a single point of measurement outside thehousehold. The aim of this approach is to get optimal energyconsumption and avoid energy wastage. Intrusive loadmonitoring (ILM is the process of identify and locate singledevices through the use of sensing systems to support control,monitor and intervention of such devices. The aim of thisapproach is to offer a base for the development of importantapplications for remote and automatic intervention of energyconsumption inside buildings and homes as well. For generalpurposes this paper states a general framework of NILM andILM approaches.Appliance discerns can be tackled using approaches fromdata mining and machine learning, finding out the techniquesthat fit the best this requirements, is a key factor for achievingfeasible and suitable appliance load monitoring solutions. Thispaper presents common and interesting methods used.Privacy concerns have been one of the bigger obstacles forimplementing a widespread adoption of these solutions; despitethis fact, developed countries like those inside the EU and theUK have established a deadline for the implementation ofsmart meters in the whole country, whereas USA governmentstill struggles with the acceptance of this solution by itscitizens.The implementation of security over these approachesalong with fine-grained energy monitoring would lead to abetter public agreement of these solutions and hence a fasteradoption of such approaches. This paper reveals a lack ofsecurity over these approaches with a real scenario.

  15. The Ramsar Sites of Disko, West Greenland

    DEFF Research Database (Denmark)

    Egevang, C.; Boertmann, D.

    The three Ramsar sites of Disko Island in West Greenland were surveyed for breeding and staging waterbirds in July 2001. Two of the areas (no. 1 and 2) held a high diversity of waterbirds and proved to be of international importance for the Greenland white-fronted goose, while the third (no. 3......) held very few waterbirds and hardly meet any of the specific waterbird criteria of the Ramsar convention...

  16. Modelling the response of stable water isotopes in Greenland precipitation to orbital configurations of the previous interglacial

    Directory of Open Access Journals (Sweden)

    Jesper Sjolte

    2014-09-01

    Full Text Available The relation between δ 18O of precipitation and temperature has been used in numerous studies to reconstruct past temperatures at ice core sites in Greenland and Antarctica. During the past two decades, it has become clear that the slope between δ 18O and temperature varies in both space and time. Here, we use a general circulation model driven by changes in orbital parameters to investigate the Greenland δ 18O–temperature relation for the previous interglacial, the Eemian. In our analysis, we focus on changes in the moisture source regions, and the results underline the importance of taking the seasonality of climate change into account. The orbitally driven experiments show that continental evaporation over North America increases during summer in the warm parts of the Eemian, while marine evaporation decreases. This likely flattens the Greenland δ 18O response to temperature during summer. Since the main climate change in the experiments occurs during summer this adds to a limited response of δ 18O, which is more strongly tied to temperature during winter than during summer. A south–west to north–east gradient in the δ 18O–temperature slope is also evident for Greenland, with low slopes in the south–west and steeper slopes in the north–east. This probably reflects the proportion of continental moisture and Arctic moisture arriving in Greenland, with more continental moisture in the south–west and less in the north–east, and vice versa for the Arctic moisture.

  17. Earthquake Activity in the North Greenland Region

    Science.gov (United States)

    Larsen, Tine B.; Dahl-Jensen, Trine; Voss, Peter H.

    2017-04-01

    Many local and regional earthquakes are recorded on a daily basis in northern Greenland. The majority of the earthquakes originate at the Arctic plate boundary between the Eurasian and the North American plates. Particularly active regions away from the plate boundary are found in NE Greenland and in northern Baffin Bay. The seismograph coverage in the region is sparse with the main seismograph stations located at the military outpost, Stations Nord (NOR), the weather station outpost Danmarkshavn (DAG), Thule Airbase (TULEG), and the former ice core drilling camp (NEEM) in the middle of the Greenland ice sheet. Furthermore, data is available from Alert (ALE), Resolute (RES), and other seismographs in northern Canada as well as from a temporary deployment of BroadBand seismographs along the north coast of Greenland from 2004 to 2007. The recorded earthquakes range in magnitude from less than 2 to a 4.8 event, the largest in NE Greenland, and a 5.7 event, the largest recorded in northern Baffin Bay. The larger events are recorded widely in the region allowing for focal mechanisms to be calculated. Only a few existing focal mechanisms for the region can be found in the ISC bulletin. Two in NE Greenland representing primarily normal faulting and one in Baffin Bay resulting from reverse faulting. New calculations of focal mechanisms for the region will be presented as well as improved hypocenters resulting from analysis involving temporary stations and regional stations that are not included in routine processing.

  18. Vapour Intrusion into Buildings - A Literature Review

    Science.gov (United States)

    This chapter provides a review of recent research on vapour intrusion of volatile organic compounds (VOCs) into buildings. The chapter builds on a report from Tillman and Weaver (2005) which reviewed the literature on vapour intrusion through 2005. Firstly, the term ‘vapour intru...

  19. Mass loss from the southern half of the Greenland Ice Sheet since the Little Ice Age

    DEFF Research Database (Denmark)

    Kjeldsen, Kristian Kjellerup; Kjær, Kurt H.; Bjørk, Anders Anker

    Northern hemisphere temperatures reached their Holocene minimum and most glaciers reached their maximum during The Little Ice Age (LIA), but the timing of specific cold intervals is site-specific. In southern Greenland, we have compiled data from organic matter incorporated in LIA sediments, used...... as a signal for ice-free terrain being overridden by LIA glacier advances, and data from threshold lakes showing the onset of glacier-fed lakes, thus revealing the advance-maximum phase initiating the LIA. Finally, we have compiled lichenometry results indicating the onset of bedrock vegetation succeeding ice...... the Arctic. Furthermore, the glacier response seems to be mirrored by a oceanic cooling between 500-1000 AD, followed by onset of the LIA at 1150-1250 AD as seen in the relative strength of warm subsurface water and the influence of the East Greenland Current....

  20. Intrusion Preventing System using Intrusion Detection System Decision Tree Data Mining

    Directory of Open Access Journals (Sweden)

    Syurahbil

    2009-01-01

    Full Text Available Problem statement: To distinguish the activities of the network traffic that the intrusion and normal is very difficult and to need much time consuming. An analyst must review all the data that large and wide to find the sequence of intrusion on the network connection. Therefore, it needs a way that can detect network intrusion to reflect the current network traffics. Approach: In this study, a novel method to find intrusion characteristic for IDS using decision tree machine learning of data mining technique was proposed. Method used to generate of rules is classification by ID3 algorithm of decision tree. Results: These rules can determine of intrusion characteristics then to implement in the firewall policy rules as prevention. Conclusion: Combination of IDS and firewall so-called the IPS, so that besides detecting the existence of intrusion also can execute by doing deny of intrusion as prevention.

  1. Feeding ecology of Greenland halibut and sandeel larvae off West Greenland

    DEFF Research Database (Denmark)

    Stenberg, Claus; Munk, Peter; Folkvord, A.

    2006-01-01

    Feeding ecology of Greenland halibut (Gr. halibut) (Reinhardtius hippoglossoides) and sandeel (Ammodytes sp.) larvae on the West Greenland shelf was studied during the main part of the productive season (May, June and July). Copepods were the main prey item for larval Gr. halibut and sandeel, con...

  2. Spaceborne measurement of Greenland ice sheet changes: the ESA Greenland CCI project

    DEFF Research Database (Denmark)

    Forsberg, René; Sørensen, Louise Sandberg; Meister, Rakia

    The ESA “Greenland_ice_sheet_cci” project is currently making past and present space measurements of Greenland ice sheet changes available for use by scientists, stakeholders and the general public. The data are part of a large set of ECV’s (Essential Climate Variables) made available by the ESA ...

  3. The HIV epidemic in Greenland - a slow spreading infection among adult heterosexual Greenlanders

    DEFF Research Database (Denmark)

    Bjørn-Mortensen, Karen; Ladefoged, Karin; Obel, Niels;

    2013-01-01

    We aimed to characterise the HIV epidemic in Greenland and to determine incidence, prevalence, mortality rates (MR) and specific causes of deaths.......We aimed to characterise the HIV epidemic in Greenland and to determine incidence, prevalence, mortality rates (MR) and specific causes of deaths....

  4. Experimental study of the interplay between magmatic rift intrusion and flank instability with application to the 2001 Mount Etna eruption

    KAUST Repository

    Le Corvec, Nicolas

    2014-07-01

    Mount Etna volcano is subject to transient magmatic intrusions and flank movement. The east flank of the edifice, in particular, is moving eastward and is dissected by the Timpe Fault System. The relationship of this eastward motion with intrusions and tectonic fault motion, however, remains poorly constrained. Here we explore this relationship by using analogue experiments that are designed to simulate magmatic rift intrusion, flank movement, and fault activity before, during, and after a magmatic intrusion episode. Using particle image velocimetry allows for a precise temporal and spatial analysis of the development and activity of fault systems. The results show that the occurrence of rift intrusion episodes has a direct effect on fault activity. In such a situation, fault activity may occur or may be hindered, depending on the interplay of fault displacement and flank acceleration in response to dike intrusion. Our results demonstrate that a complex interplay may exist between an active tectonic fault system and magmatically induced flank instability. Episodes of magmatic intrusion change the intensity pattern of horizontal flank displacements and may hinder or activate associated faults. We further compare our results with the GPS data of the Mount Etna 2001 eruption and intrusion. We find that syneruptive displacement rates at the Timpe Fault System have differed from the preeruptive or posteruptive periods, which shows a good agreement of both the experimental and the GPS data. Therefore, understanding the flank instability and flank stability at Mount Etna requires consideration of both tectonic and magmatic forcing. Key Points Analyzing Mount Etna east flank dynamics during the 2001 eruption Good correlation between analogue models and GPS data Understanding the different behavior of faulting before/during/after an eruption © 2014. American Geophysical Union. All Rights Reserved.

  5. Quantification of the intrusion process at Kīlauea volcano, Hawai'i

    Science.gov (United States)

    Wright, Thomas L.; Marsh, Bruce

    2016-12-01

    The characteristic size of two types of intrusions identified beneath Kīlauea's East Rift zone are uniquely estimated by combining time constraints from fractional crystallization and the rates of magma solidification during cooling. Some intrusions were rapidly emplaced as dikes, but stalled before reaching the surface, and cooled and crystallized to feed later fractionated eruptions. More specifically, using the observed time interval between initial emplacement and eruption of fractionated lava, whose degree of fractionation is estimated from petrologic mixing calculations, the extent of solidification or cooling needed to produce this amount of fractionation can be directly inferred. And from the known erupted volumes the spatial extent or size of this fractionated volume can be analytically related to the full size of the source body itself. Two examples yield dike widths of 82 and 68 m. Other intrusions remain close to the east rift magma transport path and are observed to last for decades or longer as viable magma bodies that may participate in feeding later eruptions. The thickness of semi-permanent reservoirs near the East Rift Zone magma transport path can be estimated by assuming a resupply rate that is sufficiently frequent to restrict cooling to feeding shallow intrusions, which are accompanied by intense rift earthquake swarms and are often associated with eruptions. These calculations show that long-term heating of the wallrock of the magma transport paths serves to slow conduit cooling, which may be partly responsible for sustaining long East Rift Zone eruptions. Adjacent to the vertical transport path beneath Kīlauea's summit, the combined effects of heating and ever-increasing magma supply rate may have forced a commensurate enlarging of the conduit, perhaps explaining the occurrence of a temporary burst of deep (5-15 km) long-period earthquake swarms between 1987 and 1992.

  6. Nivation forms and processes in unconsolidated sediments, NE Greenland

    DEFF Research Database (Denmark)

    Christiansen, Hanne Hvidtfeldt

    1998-01-01

    Nivation, Nivation Hollow, Nival Backwall Faliure, Active layer Interflow, Pronival alluvial fans, NE Greenland......Nivation, Nivation Hollow, Nival Backwall Faliure, Active layer Interflow, Pronival alluvial fans, NE Greenland...

  7. Geophysical Investigations of Saline Permafrost at Ilulissat, Greenland

    DEFF Research Database (Denmark)

    Ingeman-Nielsen, Thomas; Foged, Niels Nielsen; Butzbach, Rune

    2008-01-01

    The technical properties and general state of permafrost in Greenland is not well documented. A new coordinated investigation has been initiated, for ground temperature measurements and permafrost mapping in Greenlandic towns in sporadic, discontinuous and continuous permafrost zones. We present ...

  8. The influence of regional circulation patterns on wet and dry mineral dust and sea salt deposition over Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Hutterli, M.A. [University of Bern, Physics Institute, Bern (Switzerland); British Antarctic Survey, Physical Sciences Division, Cambridge (United Kingdom); Crueger, T. [Max-Planck-Institute for Meteorology, Hamburg (Germany); Fischer, H. [Alfred-Wegener-Institute for Polar and Marine Research, Bremerhaven (Germany); Andersen, K.K.; Siggaard-Andersen, M.L. [University of Copenhagen, Niels Bohr Institute, Copenhagen (Denmark); Raible, C.C.; Stocker, T.F. [University of Bern, Physics Institute, Bern (Switzerland); McConnell, J.R. [Desert Research Institute, Reno, NV (United States); Bales, R.C.; Burkhart, J.F. [University of California, Merced, Atwater, CA (United States)

    2007-05-15

    Annually resolved ice core records from different regions over the Greenland ice sheet (GrIS) are used to investigate the spatial and temporal variability of calcium (Ca{sup 2+}, mainly from mineral dust) and sodium (Na{sup +}, mainly from sea salt) deposition. Cores of high common inter-annual variability are grouped with an EOF analysis, resulting in regionally representative Ca{sup 2+} and Na{sup +} records for northeastern and central Greenland. Utilizing a regression and validation method with ERA-40 reanalysis data, these common records are associated with distinct regional atmospheric circulation patterns over the North American Arctic, Greenland, and Central to Northern Europe. These patterns are interpreted in terms of transport and deposition of the impurities. In the northeastern part of the GrIS sea salt records reflect the intrusion of marine air masses from southeasterly flow. A large fraction of the Ca{sup 2+} variability in this region is connected to a circulation pattern suggesting transport from the west and dry deposition. This pattern is consistent with the current understanding of a predominantly Asian source of the dust deposited over the GrIS. However, our results also indicate that a significant fraction of the inter-annual dust variability in NE and Central Greenland is determined by the frequency and intensity of wet deposition during the season of high atmospheric dust loading, rather than representing the variability of the Asian dust source and/or long-range transport to Greenland. The variances in the regional proxy records explained by the streamfunction patterns are high enough to permit reconstructions of the corresponding regional deposition regimes and the associated circulation patterns. (orig.)

  9. The role of estrogen in intrusive memories.

    Science.gov (United States)

    Cheung, Jessica; Chervonsky, Liza; Felmingham, Kim L; Bryant, Richard A

    2013-11-01

    Intrusive memories are highly vivid, emotional and involuntary recollections which cause significant distress across psychological disorders including posttraumatic disorder (PTSD). Recent evidence has potentially extended our understanding of the development of intrusive memories by identifying biological factors which significantly impact on memories for emotionally arousing stimuli. This study investigated the role of stress on the development of intrusions for negative and neutral images, and indexed the potential contributions of sex (estrogen and progesterone) and stress (noradrenaline and cortisol) hormones. Whilst viewing the images, half the participants underwent a cold pressor stress (CPS) procedure to induce stress while the control participants immersed their hands in warm water. Saliva samples were collected to index estrogen, progesterone and noradrenergic and cortisol response. Participants (55 university students, 26 men, 29 women) viewed a series of negatively arousing and neutral images. Participants completed recall and intrusions measures 2 days later. Negative images resulted in greater recall and more intrusions than neutral images. In the cold water condition females recalled fewer neutral memories than males. Cortisol increase predicted decreased recall of negative memories in males, and estrogen predicted increased intrusions of negative images in women. These findings are consistent with evidence that circulating levels of ovarian hormones influence memory for emotionally arousing events, and provides the first evidence of the influence of sex hormones on intrusive memories. These results provide one possible explanation for the higher incidence of anxiety disorders in women.

  10. Gastrointestinal Parasites of Two Populations of Arctic Foxes (Vulpes lagopus) from Northeast Greenland

    DEFF Research Database (Denmark)

    Andreassen, P.N.S.; Schmidt, Niels Martin; Kapel, Christian M. O.

    2017-01-01

    Parasitological examination of 275 faecal samples from Arctic foxes (Vulpes lagopus) collected at Zackenberg Valley and Karupelv Valley in north-east Greenland from 2006 to 2008 was conducted using sieving and microscopy. Overall, 125 (45.5%) samples contained parasite eggs of Taenia crassiceps......, Taenia serialis, Toxascaris leonina, Eucoleus boehmi, Physalopteridae and Ancylostomatidae, and Strongyloides-like larvae. As long-term ecological studies are conducted at both sampling locations, the present findings constitute a baseline data set for further parasitological monitoring....

  11. Signature Based Intrusion Detection System Using SNORT

    Directory of Open Access Journals (Sweden)

    Vinod Kumar

    2012-11-01

    Full Text Available Now a day’s Intrusion Detection systems plays very important role in Network security. As the use of internet is growing rapidly the possibility of attack is also increasing in that ratio. People are using signature based IDS’s. Snort is mostly used signature based IDS because of it is open source software. World widely it is used in intrusion detection and prevention domain. Basic analysis and security engine (BASE is also used to see the alerts generated by Snort. In the paper we have implementation the signature based intrusion detection using Snort. Our work will help to novel user to understand the concept of Snort based IDS.

  12. Pneumatization and otitis media in Greenlandic Inuit before European colonization

    DEFF Research Database (Denmark)

    Homøe, P; Lynnerup, N; Skovgaard, L T

    1995-01-01

    A total of 127 Greenlandic Inuit crania from before the European colonization of Greenland and deriving from the West (W), Southeast (SE), and Northeast (NE) coast of Greenland were examined for sequelae of infectious middle ear disease (IMED) and for a relationship between the size of the pneuma...

  13. Reuse of harbour sediments in the Greenlandic construction industry

    DEFF Research Database (Denmark)

    Belmonte, Louise Josefine; Kirkelund, Gunvor Marie; Ottosen, Lisbeth M.

    2010-01-01

    The purpose of this study is to investigate possibilities of using harbour sediments from the Greenlandic harbours as substitutes in the Greenlandic construction industry, mainly for concrete production and road construction. Materials for use in the Greenlandic construction industry are shipped...

  14. Clouds enhance Greenland ice sheet meltwater runoff

    Science.gov (United States)

    Van Tricht, Kristof; Lhermitte, Stef; Lenaerts, Jan T. M.; Gorodetskaya, Irina V.; L'Ecuyer, Tristan S.; Noël, Brice; van den Broeke, Michiel R.; Turner, David D.; van Lipzig, Nicole P. M.

    2016-04-01

    The Greenland ice sheet has become one of the main contributors to global sea level rise, predominantly through increased meltwater runoff. The main drivers of Greenland ice sheet runoff, however, remain poorly understood. Here we show that clouds enhance meltwater runoff by about one-third relative to clear skies, using a unique combination of active satellite observations, climate model data and snow model simulations. This impact results from a cloud radiative effect of 29.5 (±5.2) W m-2. Contrary to conventional wisdom, however, the Greenland ice sheet responds to this energy through a new pathway by which clouds reduce meltwater refreezing as opposed to increasing surface melt directly, thereby accelerating bare-ice exposure and enhancing meltwater runoff. The high sensitivity of the Greenland ice sheet to both ice-only and liquid-bearing clouds highlights the need for accurate cloud representations in climate models, to better predict future contributions of the Greenland ice sheet to global sea level rise.

  15. Destabilization of the Northeast Greenland Ice Stream

    Science.gov (United States)

    Korsgaard, N. J.; Khan, S. A.; Kjaer, K.; Bevis, M. G.; Bamber, J. L.; Kjeldsen, K. K.; Bjork, A. A.; Wahr, J. M.; Stearns, L. A.; van den Broeke, M. R.; Muresan, I. S.; Larsen, N. K.

    2013-12-01

    The Greenland Ice Sheet (GrIS) has been one of the largest contributors to global sea level rise over the last 20 years, accounting for c. 0.5 of a total of c. 3.2 mm yr-1. A significant portion of this contribution is associated with the speed up of glaciers in southeast and northwest Greenland. Here, we reveal that the Northeast Greenland Ice Stream (NEGIS), which extends more than 600 km into the interior of the ice sheet, is now undergoing dynamic thinning after more than a quarter of a century of stability. This sector of the GrIS is of particular interest in sea level projections, because the glacier flows into a large submarine basin with a negative bed slope near the grounding line. Our findings unfold the next step in mass loss of the GrIS as we show a heightened risk of rapid sustained loss from Northeast Greenland on top of the thinning in Southeast and Northwestern Greenland.

  16. Clouds enhance Greenland ice sheet meltwater runoff.

    Science.gov (United States)

    Van Tricht, K; Lhermitte, S; Lenaerts, J T M; Gorodetskaya, I V; L'Ecuyer, T S; Noël, B; van den Broeke, M R; Turner, D D; van Lipzig, N P M

    2016-01-12

    The Greenland ice sheet has become one of the main contributors to global sea level rise, predominantly through increased meltwater runoff. The main drivers of Greenland ice sheet runoff, however, remain poorly understood. Here we show that clouds enhance meltwater runoff by about one-third relative to clear skies, using a unique combination of active satellite observations, climate model data and snow model simulations. This impact results from a cloud radiative effect of 29.5 (±5.2) W m(-2). Contrary to conventional wisdom, however, the Greenland ice sheet responds to this energy through a new pathway by which clouds reduce meltwater refreezing as opposed to increasing surface melt directly, thereby accelerating bare-ice exposure and enhancing meltwater runoff. The high sensitivity of the Greenland ice sheet to both ice-only and liquid-bearing clouds highlights the need for accurate cloud representations in climate models, to better predict future contributions of the Greenland ice sheet to global sea level rise.

  17. Clouds enhance Greenland ice sheet meltwater runoff

    Science.gov (United States)

    Van Tricht, K.; Lhermitte, S.; Lenaerts, J. T. M.; Gorodetskaya, I. V.; L'Ecuyer, T. S.; Noël, B.; van den Broeke, M. R.; Turner, D. D.; van Lipzig, N. P. M.

    2016-01-01

    The Greenland ice sheet has become one of the main contributors to global sea level rise, predominantly through increased meltwater runoff. The main drivers of Greenland ice sheet runoff, however, remain poorly understood. Here we show that clouds enhance meltwater runoff by about one-third relative to clear skies, using a unique combination of active satellite observations, climate model data and snow model simulations. This impact results from a cloud radiative effect of 29.5 (±5.2) W m−2. Contrary to conventional wisdom, however, the Greenland ice sheet responds to this energy through a new pathway by which clouds reduce meltwater refreezing as opposed to increasing surface melt directly, thereby accelerating bare-ice exposure and enhancing meltwater runoff. The high sensitivity of the Greenland ice sheet to both ice-only and liquid-bearing clouds highlights the need for accurate cloud representations in climate models, to better predict future contributions of the Greenland ice sheet to global sea level rise. PMID:26756470

  18. Glaciation and erosion of Eastern Greenland at the Eocene-Oligocene transition: Insights from low-temperature thermochronology

    Science.gov (United States)

    Bernard, Thomas; Steer, Philippe; Gallagher, Kerry; Szulc, Adam; Whittam, Andrew

    2016-04-01

    Climate cooling through the Late Cenozoic was important in the evolution of glaciated mountain ranges. While the onset of accelerated Cenozoic exhumation is generally associated with the Quaternary at mid-latitudes, coincident with the local onset of glaciation, some high-latitude passive margins may have experienced earlier glaciation starting at 30-38 Ma or even 45 Ma. To address this issue, we use a set of new AFT data from 16 sub-vertical profiles sampled along the fjords of the central Eastern Greenland margin between 68° and 76° N, combined with new apatite (U-Th-Sm)/He (AHe) data from selected profiles. To infer thermal histories and exhumation from these profiles, we use the software QTQt. The modeling results show a major phase of exhumation in the East Greenland margin between 68° and 76° N starting at 30±5 Ma. The spatial distribution of the exhumation shows that normal faulting on East Greenland margin had no resolvable influence on exhumation related to the cooling phase. However, the timing is coincident with the dramatic worldwide fall of surface temperature at the Eocene-Oligocene transition. We therefore suggest that a transition from an Eocene fluvial to an Oligocene glacial-dominated landscape triggered a period of enhanced erosion. We infer from the thermal histories that around 2.7±1.9 km of erosion occurred close to the coast since the Eocene-Oligocene transition. This amount of erosion is consistent with the incision of the fjords and with the effective removal of 2.3±1.5 km of basalt thickness, deduced by the thermal modeling of a heating phase at 55±5 Ma. This phase of erosion is most strongly evidenced near the coast, suggesting either that continental ice extent was limited to the coastal areas or that erosion was less efficient outside these areas, leading to no obvious signal in thermochronometric data further north. Overall, this study provides the first onshore evidence of the onset of continental ice in East Greenland margin

  19. Grey-theory based intrusion detection model

    Institute of Scientific and Technical Information of China (English)

    Qin Boping; Zhou Xianwei; Yang Jun; Song Cunyi

    2006-01-01

    To solve the problem that current intrusion detection model needs large-scale data in formulating the model in real-time use, an intrusion detection system model based on grey theory (GTIDS) is presented. Grey theory has merits of fewer requirements on original data scale, less limitation of the distribution pattern and simpler algorithm in modeling.With these merits GTIDS constructs model according to partial time sequence for rapid detect on intrusive act in secure system. In this detection model rate of false drop and false retrieval are effectively reduced through twice modeling and repeated detect on target data. Furthermore, GTIDS framework and specific process of modeling algorithm are presented. The affectivity of GTIDS is proved through emulated experiments comparing snort and next-generation intrusion detection expert system (NIDES) in SRI international.

  20. Intrusion Detection Architecture Utilizing Graphics Processors

    Directory of Open Access Journals (Sweden)

    Branislav Madoš

    2012-12-01

    Full Text Available With the thriving technology and the great increase in the usage of computer networks, the risk of having these network to be under attacks have been increased. Number of techniques have been created and designed to help in detecting and/or preventing such attacks. One common technique is the use of Intrusion Detection Systems (IDS. Today, number of open sources and commercial IDS are available to match enterprises requirements. However, the performance of these systems is still the main concern. This paper examines perceptions of intrusion detection architecture implementation, resulting from the use of graphics processor. It discusses recent research activities, developments and problems of operating systems security. Some exploratory evidence is presented that shows capabilities of using graphical processors and intrusion detection systems. The focus is on how knowledge experienced throughout the graphics processor inclusion has played out in the design of intrusion detection architecture that is seen as an opportunity to strengthen research expertise.

  1. Autonomous Rule Creation for Intrusion Detection

    Energy Technology Data Exchange (ETDEWEB)

    Todd Vollmer; Jim Alves-Foss; Milos Manic

    2011-04-01

    Many computational intelligence techniques for anomaly based network intrusion detection can be found in literature. Translating a newly discovered intrusion recognition criteria into a distributable rule can be a human intensive effort. This paper explores a multi-modal genetic algorithm solution for autonomous rule creation. This algorithm focuses on the process of creating rules once an intrusion has been identified, rather than the evolution of rules to provide a solution for intrusion detection. The algorithm was demonstrated on anomalous ICMP network packets (input) and Snort rules (output of the algorithm). Output rules were sorted according to a fitness value and any duplicates were removed. The experimental results on ten test cases demonstrated a 100 percent rule alert rate. Out of 33,804 test packets 3 produced false positives. Each test case produced a minimum of three rule variations that could be used as candidates for a production system.

  2. Periodontal changes following molar intrusion with miniscrews

    Directory of Open Access Journals (Sweden)

    Shahin Bayani

    2015-01-01

    Conclusion: Within the limitations of this study, these results suggest that not only periodontal status was not negatively affected by intrusion, but also there were signs of periodontal improvement including attachment gain and shortening of clinical crown height.

  3. Autonomous Rule Creation for Intrusion Detection

    Energy Technology Data Exchange (ETDEWEB)

    Todd Vollmer; Jim Alves-Foss; Milos Manic

    2011-04-01

    Many computational intelligence techniques for anomaly based network intrusion detection can be found in literature. Translating a newly discovered intrusion recognition criteria into a distributable rule can be a human intensive effort. This paper explores a multi-modal genetic algorithm solution for autonomous rule creation. This algorithm focuses on the process of creating rules once an intrusion has been identified, rather than the evolution of rules to provide a solution for intrusion detection. The algorithm was demonstrated on anomalous ICMP network packets (input) and Snort rules (output of the algorithm). Output rules were sorted according to a fitness value and any duplicates were removed. The experimental results on ten test cases demonstrated a 100 percent rule alert rate. Out of 33,804 test packets 3 produced false positives. Each test case produced a minimum of three rule variations that could be used as candidates for a production system.

  4. A phased approach to network intrusion detection

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, K.A.; DuBois, D.H.; Stallings, C.A.

    1991-01-01

    This paper describes the design and development of a prototype intrusion detection system for the Los Alamos National Laboratory's Integrated Computing Network (ICN). The development of this system is based on three basic assumptions: (1) that statistical analysis of computer system and user activates may be used to characterize normal system and user behavior, and that given the resulting statistical profiles, behavior which deviates beyond certain bounds can be detected, (2) that expert system techniques can be applied to security auditing and intrusion detection, and (3) that successful intrusion detection may take place while monitoring a limited set of network activities. The Network Anomaly Detection and Intrusion Reporter (NADIR) design intent was to duplicate and improve the audit record review activities which had previously been undertaken by security personnel, to replace the manual review of audit logs with a near realtime expert system.

  5. Immune Based Intrusion Detector Generating Algorithm

    Institute of Scientific and Technical Information of China (English)

    DONG Xiao-mei; YU Ge; XIANG Guang

    2005-01-01

    Immune-based intrusion detection approaches are studied. The methods of constructing self set and generating mature detectors are researched and improved. A binary encoding based self set construction method is applied. First,the traditional mature detector generating algorithm is improved to generate mature detectors and detect intrusions faster. Then, a novel mature detector generating algorithm is proposed based on the negative selection mechanism. Accord ing to the algorithm, less mature detectors are needed to detect the abnormal activities in the network. Therefore, the speed of generating mature detectors and intrusion detection is improved. By comparing with those based on existing algo rithms, the intrusion detection system based on the algorithm has higher speed and accuracy.

  6. A Citizen's Guide to Vapor Intrusion Mitigation

    Science.gov (United States)

    This guide describes how vapor intrusion is the movement of chemical vapors from contaminated soil and groundwater into nearby buildings.Vapors primarily enter through openings in the building foundation or basement walls.

  7. Intrusion Detection System Using Advanced Honeypots

    CERN Document Server

    Singh, Ram Kumar

    2009-01-01

    The exponential growth of Internet traffic has made public servers increasingly vulnerable to unauthorized accesses and intrusions. In addition to maintaining low latency for the client, filtering unauthorized accesses has become one of the major concerns of a server maintainer. This implementation of an Intrusion Detection System distinguishes between the traffic coming from clients and the traffic originated from the attackers, in an attempt to simultaneously mitigate the problems of both latency and security. We then present the results of a series of stress and scalability tests, and suggest a number of potential uses for such a system. As computer attacks are becoming more and more difficult to identify the need for better and more efficient intrusion detection systems increases. The main problem with current intrusion detection systems is high rate of false alarms. Using honeypots provides effective solution to increase the security.

  8. Multibeam Mapping of Remote Fjords in Southeast-Greenland

    Science.gov (United States)

    Weinrebe, W.; Kjaer, K. H.; Kjeldsen, K. K.; Bjork, A. A.

    2015-12-01

    The fjords of Southeast-Greenland are among the most remote areas of the Northern Hemisphere. Access to this area is hampered by a broad belt of sea ice floating along the East-Greenland coast from North to South. Consequently, the majority of those fjords have never been surveyed in detail until now. During an expedition by the Center of GeoGenetics of the University of Copenhagen in summer of 2014 we were able to map the Skjoldungen Fjord system with multibeam bathymetry. The topsail schooner ACTIV, built 1951 as a cargo ship to supply remote settlements in Greenland was chosen for the expedition. Though a vintage vessel, the ACTIV was well suited to cross the belt of sea ice and to cruise the ice covered fjords. A portable ELAC-Seabeam 1050 multibeam system was temporarily installed on the vessel. The two transducer of the system were mounted at the lower end of a 6 m long pole attached outboard at port side to the hull of the vessel. Though the installation was quite demanding without any winches or cranes, the construction was sufficiently stable and easy to manage throughout the entire cruise. Nearly the entire fjord system, leaving only a small gap of 5 km at the innermost part and small stripes close to the shorelines could be surveyed during the cruise. For the first time, a comprehensive map of Skjoldungen Fjord is now available. The map displays water depths from close to zero up to 800 m, the deepest part along a stretch of about 10 km in the Southwest. The bathymetry of the northern fjord is remarkably different from the southern fjord: the southern fjord features an outer deep part showing water depths between 500 m and 800 m and a shallow inner part with depths less than 300 m and a prominent sill in between. The northern fjord shows a more gradual increase of water depths from 200 m in the inner part to 600 m at the entrance.

  9. Cultural change and mental health in Greenland

    DEFF Research Database (Denmark)

    Bjerregaard, Peter; Curtis, Tine; Greenland, Population Study

    2002-01-01

    to the General Health Questionnaire (GHQ-12) and the prevalence of suicidal thoughts were studied in relation to childhood residence and father's occupation, current residence, and language. The statistical methods included logistic regression and graphical independence models. The results indicated a U......-shaped association in Greenland of GHQ-cases with age and a high prevalence of suicidal thoughts among young people; a low prevalence of GHQ-cases among those who were bilingual or spoke only Danish; and a high prevalence of suicidal thoughts among migrants who grew up in Denmark and among residents of the capital...... of Greenland. In Greenland, women were more often GHQ-cases and had suicidal thoughts more often than men. The association between language and GHQ-cases is presumed to operate through socioeconomic factors. It is necessary to modify the common notion that rapid societal development is in itself a cause...

  10. Future markers of the West Greenlandic

    DEFF Research Database (Denmark)

    Trondhjem, Naja Blytmann

    2010-01-01

    Abstract West Greenlandic, a polysynthetic language, belongs to Inuit languages. In Inuktitut (Canada) and West Greenlandic (Inuit languages) tense is marked by optional tense suffixes and in both languages the temporal systems are based on a future/ non-future opposition. In Inuktitut the tense......, and it is used when none of the others can be used. It seems that some of the tense suffixes i.e. past (-sima, perfective, perfect, preterite) and future (-ler, begin, be about to, near future) originally had a more or less concrete aspectual meanings and have developed into more abstract tense meanings...... suffixes have developed a complicated remoteness system. In West Greenlandic the future tense suffixes have a distinction between vague and inevitable future, and the past time suffixes have developed different perfect meanings. In Iñupiaq (Alaska), the temporal system is based on an opposition between...

  11. Physical activity in Greenland - a methodological perspective

    DEFF Research Database (Denmark)

    Dahl-Petersen, Inger

    Title: Physical activity in Greenland - a methodical perspective Inger Dahl-Petersen, National Institute of Public Health, Copenhagen, Denmark Purpose:   The present study is the first population-based study in Greenland with information on physical activity using The International Physical...... Participants in a cross-sectional population survey representative of towns and villages in West Greenland completed an interviewer-administered questionnaire about their physical activity. The long version of The International Physical Activity Questionnaire (IPAQ) was used to measure time spent on physical.......001). Less energy was used in leisure time among women living in a village (Pphysical activity in leisure time, home, work and transportation and provide information on both time and energy...

  12. Lead sources in human diet in Greenland

    DEFF Research Database (Denmark)

    Bjerregaard, Peter; Johansen, Poul; Mulvad, Gert

    2004-01-01

    Although blood lead levels have declined in Greenland, they are still elevated despite the fact that lead levels in the Greenland environment are very low. Fragments of lead shot in game birds have been suggested as an important source of dietary exposure, and meals of sea birds, particularly eider......, contain high concentrations of lead. In a cross-sectional population survey in Greenland in 1993-1994, blood lead adjusted for age and sex was found to be associated with the reported consumption of sea birds. Participants reporting less than weekly intake of sea birds had blood lead concentrations...... of approximately 75 microg/L, whereas those who reported eating sea birds several times a week had concentrations of approximately 110 microg/L, and those who reported daily intake had concentrations of 170 microg/L (p = 0.01). Blood lead was not associated with dietary exposure to other local or imported food...

  13. Iron status markers in 224 indigenous Greenlanders

    DEFF Research Database (Denmark)

    Milman, N; Byg, K E; Mulvad, G

    2001-01-01

    OBJECTIVE: To evaluate iron status in indigenous Greenlanders and its relationship to gender, age and intake of traditional Greenlandic foods. Methods: Serum ferritin, serum transferrin saturation and haemoglobin were evaluated in a population survey in 1993-1994 comprising 224 Greenlandic...... of living. Consumption of traditional foods was assessed by questionnaire. RESULTS: Intake of traditional foods was more prevalent among elderly than among young individuals and more frequent in Uummannaq than in Ilulissat and Nuuk. Ferritin levels were higher in men than in women (p... ferritin levels were lowest in Nuuk (men, 92 microg/L; women, 40 microg/L), higher in Ilulissat (men, 104 microg/L; women, 69 microg/L) and in Uummannaq (men, 118 microg/L; women, 46 microg/L) (pferritin >200 microg/L) was lowest in Nuuk (men: 13.8%, women: 2...

  14. Driving forces in the Greenlandic urbanization

    DEFF Research Database (Denmark)

    Hendriksen, Kåre

    2014-01-01

    Generally urbanization is recognised as a natural development where the population is mowing into the larger towns driven by e.g. better job opportunities, larger product and service supply and better education and health services, and it is often argued that this is also the driving forces...... for accelerating changes in the Greenlandic settlement pattern. Resent research problematize to what extent this logic is so simple? Also in Greenland, with its 56.000 inhabitants spread over 17 so-called towns and 58 settlements, there is a clear correlation between settlement pattern and job opportunities....... This centralization has left geographical regions with limited livelihood and at the same time a lack of utilization of local resources and trade opportunities. Additionally the Greenlandic so called larger cities are ended in an un-sustainable economical situation manly depending on public financed jobs or social...

  15. Intrusion-Tolerant Architectures: Concepts and Design

    OpenAIRE

    Paulo Veríssimo; Nuno Ferreira Neves; Miguel Correia

    2003-01-01

    There is a significant body of research on distributed computing architectures, methodologies and algorithms, both in the fields of fault tolerance and security. Whilst they have taken separate paths until recently, the problems to be solved are of similar nature. In classical dependability, fault tolerance has been the workhorse of many solutions. Classical security-related work has on the other hand privileged, with few exceptions, intrusion prevention. Intrusion tolerance (IT) is a new app...

  16. Soil development as limiting factor for shrub expansion in southwestern Greenland

    Science.gov (United States)

    Caviezel, Chatrina; Hunziker, Matthias; Zoller, Oliver; Wüthrich, Christoph; Kuhn, Nikolaus J.

    2014-05-01

    Southern Greenland currently experiences an increase in summer temperatures and a prolonged growing season (Masson-Delmotte et al. 2012), resulting in an increased shrub cover at the boreal - tundra border ecotone (Normand et al. 2013). These findings suggest the beginning of a greener Greenland in which tundra vegetation is transformed to a boreal woody flora. However, vegetation at borderline ecotones is influenced by further ecologic factors than just temperature. In this study, the ecologic conditions at a selection of sites along an elevation gradient near Igaliku in southern Greenland were examined to identify potential factors limiting the expansion of woody vegetation apart from temperature. The sites differ in elevation, topography, shrub density and soil parent material. The three study sites comprise i) well established birch shrubs growing between 50 and 180 m a.s.l., where the parent material origins from the Julianehab granite (Brooks 2012); ii) extended shrub patches at about 250 m a.s.l., where the parent material consists of Gardar Sandstones and Lavas (Brooks 2012) and iii) restricted shrub patches at an elevation of 250 m a.s.l., where the soil parent material originates from the Gardar intrusions (Brooks 2012). The extent of the shrub areas, topography and soil moisture were mapped, additionally soil samples were analyzed for C-and N-content, texture including coarse fraction and pH and used as soil development indicators. Our results show that the topographic setting regulates the existence or absence of soil while the soil parent material is an important limiting factor for soil moisture. According to these findings, we suggest that a high proportion of areas where temperature increase would allow the increase of shrub cover is not suitable for a woody flora. Brooks, Kent. 2012. "A Tale of Two Intrusions—where Familiar Rock Names No Longer Suffice." Geology Today 28 (1): 13-19. doi:10.1111/j.1365-2451.2012.00815.x. Masson-Delmotte, V., D

  17. Cluster based Intrusion Detection System for Manets

    Directory of Open Access Journals (Sweden)

    Nisha Dang

    2012-07-01

    Full Text Available Manets are the ad hoc networks that are build on demand or instantly when some mobile nodes come in the mobility range of each other and decide to cooperate for data transfer and communication. Therefore there is no defined topology for Manets. They communicate in dynamic topology which continuously changes as nodes are not stable. Due to this lack of infrastructure and distributed nature they are more vulnerable for attacks and provide a good scope to malicious users to become part of the network. To prevent the security of mobile ad hoc networks many security measures are designed such as encryption algorithms, firewalls etc. But still there is some scope of malicious actions. So, Intrusion detection systems are proposed to detect any intruder in the network and its malicious activities. Cluster based intrusion detection system is also designed to restrict the intruders activities in clusters of mobile nodes. In clusters each node run some intrusion detection code to detect local as well as global intrusion. In this paper we have taken insight of intrusion detection systems and different attacks on Manet security. Then we proposed how overhead involved in cluster based intrusion detection system can be reduced.

  18. A system for distributed intrusion detection

    Energy Technology Data Exchange (ETDEWEB)

    Snapp, S.R.; Brentano, J.; Dias, G.V.; Goan, T.L.; Heberlein, L.T.; Ho, Che-Lin; Levitt, K.N.; Mukherjee, B. (California Univ., Davis, CA (USA). Div. of Computer Science); Grance, T. (Air Force Cryptologic Support Center, San Antonio, TX (USA)); Mansur, D.L.; Pon, K.L. (Lawrence Livermore National Lab., CA (USA)); Smaha, S.E. (Haystack Labs., Inc., Austin, TX (USA))

    1991-01-01

    The study of providing security in computer networks is a rapidly growing area of interest because the network is the medium over which most attacks or intrusions on computer systems are launched. One approach to solving this problem is the intrusion-detection concept, whose basic premise is that not only abandoning the existing and huge infrastructure of possibly-insecure computer and network systems is impossible, but also replacing them by totally-secure systems may not be feasible or cost effective. Previous work on intrusion-detection systems were performed on stand-alone hosts and on a broadcast local area network (LAN) environment. The focus of our present research is to extend our network intrusion-detection concept from the LAN environment to arbitarily wider areas with the network topology being arbitrary as well. The generalized distributed environment is heterogeneous, i.e., the network nodes can be hosts or servers from different vendors, or some of them could be LAN managers, like our previous work, a network security monitor (NSM), as well. The proposed architecture for this distributed intrusion-detection system consists of the following components: a host manager in each host; a LAN manager for monitoring each LAN in the system; and a central manager which is placed at a single secure location and which receives reports from various host and LAN managers to process these reports, correlate them, and detect intrusions. 11 refs., 2 figs.

  19. Geotechnical variability of permafrozen glaciomarine clays in Sdr. Strømfjord in Greenland

    DEFF Research Database (Denmark)

    Foged, Niels Nielsen; Ingeman-Nielsen, Thomas; Belmonte, Louise Josefine

    2014-01-01

    This contribution presents the geotechnical properties of some permafrozen glaciomarine clays near to the Kangerlussuaq Airport at Sdr. Strømfjord in West Greenland.This fjord system was established by glacial erosion into the bedrock consisting of Nagssugtoqidian banded gneisses with amphibolitic...... y BC) 5 km east of the Airport. Subformations found are; glaciomarine clay deposited in a coastal environment as very fine flocculated suspended matter ("rock flour"), deltaic sediments of silt and finesand and meltwater gravel and sand carried by the meltwater rivers. This sedimentation is still on...

  20. Improving the Greenlandic Greenhouse Gas Inventory

    DEFF Research Database (Denmark)

    Nielsen, Ole-Kenneth; Baunbæk, Lene; Gyldenkærne, Steen;

    The project to improve the Greenlandic greenhouse gas (GHG) inventory was undertaken due to the recommendations made by the UNFCCC review team in connection with the 2008 and 2009 submissions by the Kingdom of Denmark. The improvements made to the Greenlandic GHG emission inventory were substantial....... Firstly the full CRF format was implemented significantly increasing the level of detail. For the cross-cutting elements of the reporting a tier 1 uncertainty estimation was made. The uncertainty estimation showed a total uncertainty of the GHG emission of 5.8 %. A tier 1 key category analysis was made...

  1. Clouds enhance Greenland ice sheet meltwater runoff

    OpenAIRE

    2016-01-01

    The Greenland ice sheet has become one of the main contributors to global sea level rise, predominantly through increased meltwater runoff. The main drivers of Greenland ice sheet runoff, however, remain poorly understood. Here we show that clouds enhance meltwater runoff by about one-third relative to clear skies, using a unique combination of active satellite observations, climate model data and snow model simulations. This impact results from a cloud radiative effect of 29.5 (±5.2)Wm-2. Co...

  2. Weather Test Reference Year of Greenland

    DEFF Research Database (Denmark)

    Kragh, Jesper; Pedersen, Frank; Svendsen, Svend

    2005-01-01

    The building code of Greenland from 1982 is to be revised in the coming years fulfilling the increased demand of more energy efficient buildings. To establish appropriate levels of energy consumption for heating the weather conditions have to be analyzed. The purpose of this paper is to describe...... test reference year is constructed using measurements from the town Uummannaq located in the north part of Greenland on the west coast. The construction of the test reference years fulfills the procedures described in the standard EN ISO 15927-4 using the following main weather parameters: Dry bulb...

  3. Weather Test Reference Year of Greenland

    DEFF Research Database (Denmark)

    Kragh, Jesper; Pedersen, Frank; Svendsen, Svend

    2005-01-01

    The building code of Greenland from 1982 is to be revised in the coming years fulfilling the increased demand of more energy efficient buildings. To establish appropriate levels of energy consumption for heating the weather conditions have to be analyzed. The purpose of this paper is to describe...... test reference year is constructed using measurements from the town Uummannaq located in the north part of Greenland on the west coast. The construction of the test reference years fulfills the procedures described in the standard EN ISO 15927-4 using the following main weather parameters: Dry bulb...

  4. Mineral exploitation and development in Greenland

    DEFF Research Database (Denmark)

    Hendriksen, Kåre; Hoffmann, Birgitte; Jørgensen, Ulrik

    2014-01-01

    using immigrant and migrant labourers that work intensively while living in temporary quarters. The historic experiences of Greenland tell that a different, slower exploitation of mineral resources may contribute to social improvements and competence building thereby providing long-term improvements...... for the Greenlandic society. This point to a need for plans and the organisation of mineral exploitations that operate based on coupling local settlements and resources with mining and other forms of activities. This demands new perspectives on the content of social impact assessments as well as new criteria...

  5. Clouds enhance Greenland ice sheet meltwater runoff

    OpenAIRE

    K. Van Tricht; Lhermitte, S.; Lenaerts, J. T. M.; Gorodetskaya, I. V.; L'Ecuyer, T. S.; Noël, B; Van Den Broeke, M.R.; Turner, D. D.; Van Lipzig, N. P. M.

    2016-01-01

    The Greenland ice sheet has become one of the main contributors to global sea level rise, predominantly through increased meltwater runoff. The main drivers of Greenland ice sheet runoff, however, remain poorly understood. Here we show that clouds enhance meltwater runoff by about one-third relative to clear skies, using a unique combination of active satellite observations, climate model data and snow model simulations. This impact results from a cloud radiative effect of 29.5 (±5.2)Wm-2. Co...

  6. Vitamins and minerals in the traditional Greenland diet

    DEFF Research Database (Denmark)

    Andersen, S. M.

    The relative importance of traditional Greenlandic food items has diminished during the last decades. Today these account for 25% of the Greenland diet with a dominance of fish, seabirds, and marine mammals. This report synthesises the available information on concentrations of vitamins and miner......The relative importance of traditional Greenlandic food items has diminished during the last decades. Today these account for 25% of the Greenland diet with a dominance of fish, seabirds, and marine mammals. This report synthesises the available information on concentrations of vitamins...... and minerals in the various food items that form the traditional Greenlandic diet. However, through this diet people in Greenland are also exposed to a high intake of heavy metals and organochlorines, due to a contamination of many of these food items. In combination with information on the concentration...... of contaminants, the information about vitamins and minerals will potentially make it possible to adjust the diet in Greenland, taking both nutrients and contaminants into account...

  7. Oceans Melting Greenland: Early Results from NASA's Ocean-Ice Mission in Greenland

    DEFF Research Database (Denmark)

    Fenty, Ian; Willis, Josh K.; Khazendar, Ala

    2016-01-01

    Melting of the Greenland Ice Sheet represents a major uncertainty in projecting future rates of global sea level rise. Much of this uncertainty is related to a lack of knowledge about subsurface ocean hydrographic properties, particularly heat content, how these properties are modified across...... the continental shelf, and about the extent to which the ocean interacts with glaciers. Early results from NASA's five-year Oceans Melting Greenland (OMG) mission, based on extensive hydrographic and bathymetric surveys, suggest that many glaciers terminate in deep water and are hence vulnerable to increased...... melting due to ocean-ice interaction. OMG will track ocean conditions and ice loss at glaciers around Greenland through the year 2020, providing critical information about ocean-driven Greenland ice mass loss in a warming climate....

  8. Occurrence of anisakid nematodes in Atlantic cod (Gadus morhua) and Greenland cod (Gadus ogac), West Greenland

    DEFF Research Database (Denmark)

    Mouritsen, Kim N.; Hedeholm, Rasmus; Schack, Henriette B.;

    2010-01-01

    Anisakid nematodes commonly infect gadids, and are of economic and aesthetic importance to the commercial fishing industry in Greenland as some species are pathogenic to humans. However, very little is known about the occurrence of these parasites and their impact on the hosts in Greenland waters....... During a survey in 2005, stomach sample of 227 Atlantic cod (Gadus morhua) and 64 Greenland cod (Gadus ogac) was collected in Godthaab and Sisimiut fiord systems in West Greenland waters. All cod were dissected for stomach contents and anisakid nematodes were removed from the visceral cavity. Third stage...... nematode species regarding prevalence of infection and mean infection intensity was evident, and there was no relationship between fish condition and the intensity of nematode infections. Standardised for size, capelin-eating cod were in better condition and more heavily infected than fish subsisting...

  9. Bioaccumulation of nonylphenols and bisphenol A in the Greenland shark Somniosus microcephalus from the Greenland seawaters

    DEFF Research Database (Denmark)

    Ademollo, N.; Patrolecco, L.; Rauseo, J.

    2017-01-01

    and on the loss of biodiversity. In this work, we report the occurrence and bioaccumulation of selected endocrine-disrupting compounds (EDCs) in muscle and liver of the Greenland shark . Somniosus microcephalus, an arctic species of interest for biogeography, migration, physiology, long- and short......Recent climate changes associated with anthropogenic emissions of pollutants are triggering shifts in global biogeochemical cycles and polar marine ecosystem. The decrease of sea ice and the mechanism of ice formation/melting, may considerably have an impact on the mobility of contaminants...... been performed on the Greenland shark. Totally, muscles and liver samples were analyzed from 23 Greenland sharks (TL range 149-442. cm) sampled in W, SW, SE, and NE Greenland. Extraction of analytes from biological matrices were performed by ASE (Accelerated Solvent Extraction), followed by HPLC...

  10. Dansgaard-Oeschger cycles observed in the Greenland ReCAP ice core project

    Science.gov (United States)

    Kjær, Helle Astrid; Vallelonga, Paul; Vinther, Bo; Simonsen, Marius; Maffezzoli, Niccoló; Gkinis, Vasileios; Svensson, Anders; Jensen, Camilla Marie; Dallmayr, Remi; Spolaor, Andrea; Edwards, Ross

    2017-04-01

    The new REnland ice CAP (RECAP) ice core was drilled in summer 2015 in Greenland and measured by means of Continuous flow analysis (CFA) during the last 3 months of 2015. The Renland ice core was obtained as part of the ReCAP project, extending 584.11 meters to the bottom of the Renland ice cap located in east Greenland. The unique position on a mountain saddle above 2000 meters altitude, but close to the coast, ensures that the Renland ice core offers high accumulation, but also reaches far back in time. Results show that despite the short length the RECAP ice core holds ice all the way back to the past warm interglacial period, the Eemian. The glacial section is strongly thinned and covers on 20 meters of the ReCAP core, but nonetheless due to the high resolution of the measurements all 25 expected DO events could be identified. The record was analyzed for multiple elements including the water isotopes, forest fire tracers NH4+ and black carbon, insoluble dust particles by means of Abakus laser particle counter and the dust ion Ca2+, sea salt Na+, and sea ice proxies as well as acidity useful for finding volcanic layers to date the core. Below the glacial section another 20 meters of warm Eemian ice have been analysed. Here we present the chemistry results as obtained by continuous flow analysis (CFA) and compare the glacial section with the chemistry profile from other Greenland ice cores.

  11. Conjunctive Management of Multi-Aquifer System for Saltwater Intrusion Mitigation

    Science.gov (United States)

    Tsai, F. T. C.; Pham, H. V.

    2015-12-01

    Due to excessive groundwater withdrawals, many water wells in Baton Rouge, Louisiana experience undesirable chloride concentration because of saltwater intrusion. The study goal is to develop a conjunctive management framework that takes advantage of the Baton Rouge multi-aquifer system to mitigate saltwater intrusion. The conjunctive management framework utilizes several hydraulic control techniques to mitigate saltwater encroachment. These hydraulic control approaches include pumping well relocation, freshwater injection, saltwater scavenging, and their combinations. Specific objectives of the study are: (1) constructing scientific geologic architectures of the "800-foot" sand, the "1,000-foot" sand, the "1,200-foot" sand, the "1,500-foot" sand, the "1,700-foot" sand, and the "2,000-foot" sand, (2) developing scientific saltwater intrusion models for these sands. (3) using connector wells to draw native groundwater from one sand and inject to another sand to create hydraulic barriers to halt saltwater intrusion, (4) using scavenger wells or well couples to impede saltwater intrusion progress and reduce chloride concentration in pumping wells, and (5) reducing cones of depression by relocating and dispersing pumping wells to different sands. The study utilizes optimization techniques and newest LSU high performance computing (HPC) facilities to derive solutions. The conjunctive management framework serves as a scientific tool to assist policy makers to solve the urgent saltwater encroachment issue in the Baton Rouge area. The research results will help water companies as well as industries in East Baton Rouge Parish and neighboring parishes by reducing their saltwater intrusion threats, which in turn would sustain Capital Area economic development.

  12. Reconstructing the dynamics of the Greenland ice sheet during the last deglaciation

    Science.gov (United States)

    Keisling, Benjamin; DeConto, Robert

    2016-04-01

    Today, some outlet glaciers of the Greenland ice sheet (GrIS) are rapidly retreating and may mobilize large volumes of interior ice in the coming centuries. The last period that saw such dramatic, sustained retreat of the GrIS was the last deglaciation, when the ice sheet retreated from its Last Glacial Maximum (LGM) extent. Previous studies have used relative sea level observations to constrain changes in ice thickness and retreat timing during the deglaciation (e.g. Fleming and Lambert 2004, Simpson et al. 2009, Lecavalier et al. 2014). Here we build on these studies by isolating the drivers of ice-sheet retreat, and their spatial and temporal dynamics, during this period. Inclusion of ice-cliff failure and hydrofracturing parameterizations in our model has resulted in a better fit to paleodata for the Antarctic ice sheet, but this modeling approach has not been applied to the GrIS. Here we use a three-dimensional hybrid SSA/SIA ice-sheet model (Pollard et al. 2015) at 10km resolution over Greenland to simulate the last deglaciation. Boundary conditions for the last glacial maximum produce an LGM ice sheet with 3.81 meters sea level equivalent (m s.l.e.) of additional ice. The LGM ice sheet advances to the shelf-break in west, south, and east Greenland with an expansive ice shelf extending across Davis Strait. Applying modern atmospheric and oceanic forcing to the LGM ice sheet yields 1.25 and 1.09 m s.l.e. of melt, respectively, and 1.72 m s.l.e. for both. Ocean warming initially results in a higher rate and magnitude of retreat, but increased surface evaporation over open water results in additional accumulation that offsets losses in 10 kyr simulations. Here, we test the sensitivity of the magnitude of deglacial ice-sheet retreat to uncertainty in bedrock elevation and basal slding coefficients, the applied climate forcing, and the mass balance scheme (positive degree-day or energy balance). We also implement a deglacial climate forcing based on recently

  13. Allergen sensitization and allergen exposure in Greenlander Inuit residing in Denmark and Greenland.

    Science.gov (United States)

    Porsbjerg, C; Linstow, M L; Nepper-christensen, S C; Rasmussen, A; Korsgaard, J; Nolte, H; Backer, V

    2002-09-01

    The aim of this study was to estimate the prevalence of allergic sensitization and possible risk factors in a genetically homogenous Inuit population living under widely differing climatic and cultural conditions. A written questionnaire and skin prick test for 10 aeroallergens were obtained from 1119 adult Greenlanders residing in Denmark, Nuuk (main city in Southern Greenland) and Uummannaq (rural settlement in Northern Greenland). Allergen exposure was assessed by pollen counts, questions on pet keeping and counts of house dust mites in dust samples. The overall prevalence of at least one positive skin prick test was 22.8% in Denmark, 10.6% in Nuuk, and 6.4% in Uummannaq. In Denmark, the total birch pollen counts were 40-1000 times higher compared to Nuuk, whereas the grass pollen count was 13-30 times higher in Denmark compared to Nuuk. Dogs were held indoor with a similar frequency in Denmark and Nuuk, but much less frequently in Uummannaq. In Denmark, house dust mites were found in 72% of house holds (>10/0.1 g dust). Less than 15% of households in Greenland had measurable levels of house dust mites. The prevalence of sensitization to aeroallergens in Inuit Greenlanders differed significantly between Denmark, Nuuk and Uummannaq. These findings correlated with the observed differences in population allergen exposure in the three regions. Furthermore, differences in lifestyle factors such as educational level, stress and ethnic self-identification seemed to be associated with the risk of allergic sensitization in Greenland.

  14. Population surveys in Greenland 1993-2009

    DEFF Research Database (Denmark)

    Bjerregaard, Peter; Pedersen, Henning Sloth; Nielsen, Nina O

    2013-01-01

    The purpose of the study was to analyse temporal trends (1993-2009) of the concentrations of organochlorine contaminants (14 congeners of polychlorinated biphenyls (PCB) and 11 pesticides) in the blood of Greenland Inuit according to age and urbanisation. Statistical determinants for the contamin...

  15. Evaluation of the Doll Project in Greenland

    DEFF Research Database (Denmark)

    Wistoft, Karen

    2013-01-01

    objective of the evaluation study is to determine the short-term impact of the family and sex education including evaluating the effectiveness of this education strategy to influence Greenland teenagers' perceptions of pregnancy and parenting. The study is a pre-/posttest questionnaire survey design...

  16. The summer 2012 Greenland heat wave

    DEFF Research Database (Denmark)

    Bonne, Jean-Louis; Steen-Larsen, Hans Christian; Risi, Camille

    2015-01-01

    During 7–12 July 2012, extreme moist and warm conditions occurred over Greenland, leading to widespread surface melt. To investigate the physical processes during the atmospheric moisture transport of this event, we study the water vapor isotopic composition using surface in situ observations...

  17. Increasing mass loss from Greenland's Mittivakkat Gletscher

    DEFF Research Database (Denmark)

    Mernild, S.H.; Knudsen, N.T.; Lipscomb, W.H.

    2011-01-01

    Warming in the Arctic during the past several decades has caused glaciers to thin and retreat, and recent mass loss from the Greenland Ice Sheet is well documented. Local glaciers peripheral to the ice sheet are also retreating, but few mass-balance observations are available to quantify that ret...

  18. Ecosystem variability in west Greenland waters

    DEFF Research Database (Denmark)

    Buch, E.; Pedersen, Søren Anker; Ribergaard, M. H.

    2004-01-01

    A review of the climate conditions off West Greenland during the past 50 years shows large variability in the atmospheric, oceanographic and sea-ice variables, as well as in fish stocks. A positive relationship is found between water temperature and the recruitment of cod and redfish, whereas the...

  19. The lithospheric mantle below southern West Greenland

    DEFF Research Database (Denmark)

    Sand, Karina Krarup; Waight, Tod Earle; Pearson, D. Graham

    2009-01-01

    Geothermobarometry of primarily garnet lherzolitic xenoliths from several localities in southern West Greenland is applied to address the diamond potential, pressure and temperature distribution and the stratigraphy of the subcontinental lithospheric mantle ~600 Ma ago. The samples are from kimbe...... into the reworked Archean North of the Naqssugtoqidian deformation front....

  20. Climate science: The history of Greenland's ice

    Science.gov (United States)

    Blard, Pierre-Henri; Leduc, Guillaume; Glasser, Neil

    2016-12-01

    Global sea levels would rise by several metres if the Greenland Ice Sheet melted completely. Two studies have examined its past behaviour in an effort to evaluate its vulnerability in a warming world -- and have come to seemingly conflicting conclusions. Two geochemists and a glaciologist discuss the issues. See Letters p.252 & p.256

  1. Greenland Ice Sheet response to mid-Pliocene summer Arctic sea ice-free conditions

    Science.gov (United States)

    Koenig, S. J.; DeConto, R.; Pollard, D.

    2011-12-01

    A critical uncertainty in future predictions of climate and sea level is the response of the cryosphere. Proxy reconstructions for the mid-Pliocene Arctic Ocean (~ 3 Ma) are indicative of summer Arctic ice-free conditions and higher than modern sea surface temperatures, conditions that are analogous to projections for the end of the 21st century. We implement available mid-Pliocene boundary conditions into a fully-coupled Global Circulation Model with interactive vegetation. We use a 3-D thermo-mechanical ice sheet-shelf model to simulate the equilibrated response of the Greenland Ice Sheet (GIS) to the combined effect of reduced sea ice conditions and increased sea surface temperatures during the mid-Pliocene Warm Period. Reductions in Arctic sea ice are shown to enhance ocean/land-to-atmosphere fluxes, increasing heat and moisture transport in the high latitudes. In particular, changes in the North Atlantic exert a strong influence on the storm track and seasonal temperatures and precipitation over Greenland. Despite increased precipitation, warmer temperatures generally reduce snow mass balance. As a result, an initial present-day ice sheet forced by Pliocene climate undergoes rapid melting, limiting the ice sheet to the only highest elevations in South and East Greenland. Once the ice sheet is lost, local surface characteristics and associated feedbacks dominates Greenland climate, precluding the regrowth of the ice sheet. Depending on the initial state of the ice sheet, the equilibrated ice sheet loss is equivalent to between 5.8 to 6.4 m of sea level. We assess the sensitivity of the GIS to Pliocene forcing and internal feedbacks, adding to the understanding of land-ice sea-ice hysteresis in a world warmer than today.

  2. Modelling snow accumulation on Greenland in Eemian, glacial inception, and modern climates in a GCM

    Directory of Open Access Journals (Sweden)

    H. J. Punge

    2012-11-01

    Full Text Available Changing climate conditions on Greenland influence the snow accumulation rate and surface mass balance (SMB on the ice sheet and, ultimately, its shape. This can in turn affect local climate via orography and albedo variations and, potentially, remote areas via changes in ocean circulation triggered by melt water or calving from the ice sheet. Examining these interactions in the IPSL global model requires improving the representation of snow at the ice sheet surface. In this paper, we present a new snow scheme implemented in LMDZ, the atmospheric component of the IPSL coupled model. We analyse surface climate and SMB on the Greenland ice sheet under insolation and oceanic boundary conditions for modern, but also for two different past climates, the last glacial inception (115 kyr BP and the Eemian (126 kyr BP. While being limited by the low resolution of the general circulation model (GCM, present-day SMB is on the same order of magnitude as recent regional model findings. It is affected by a moist bias of the GCM in Western Greenland and a dry bias in the north-east. Under Eemian conditions, the SMB decreases largely, and melting affects areas in which the ice sheet surface is today at high altitude, including recent ice core drilling sites as NEEM. In contrast, glacial inception conditions lead to a higher mass balance overall due to the reduced melting in the colder summer climate. Compared to the widely applied positive degree-day (PDD parameterization of SMB, our direct modelling results suggest a weaker sensitivity of SMB to changing climatic forcing. For the Eemian climate, our model simulations using interannually varying monthly mean forcings for the ocean surface temperature and sea ice cover lead to significantly higher SMB in southern Greenland compared to simulations forced with climatological monthly means.

  3. Isotope-calibrated hydrothermal models: Geothermal implications of a model of the Skaergaard intrusion

    Energy Technology Data Exchange (ETDEWEB)

    Brikowski, T.H. [Desert Research Institute, Reno, NV (United States)

    1995-12-31

    Hydrothermal circulation models can be greatly refined by including isotopic alteration of multiple mineral phases, and calibrating predicted alteration to field observations. Analysis of predicted alteration in physical and chemical ({delta}-{delta}) space yields tight constraints on model parameters, especially permeability and isotope exchange rate constant. Applying this technique at a mafic rifting site (the Eocene Skaergaard Intrusion, eastern Greenland) yields an accurate model of the hydrothermal system, from which the geothermal aspects of the system can be estimated with considerable confidence. To match field observations of {delta}{sup 18}O alteration patterns at the Skaergaard, low average permeabilities are required (10{sup -16} m{sup 2} for basalt host rock). This results in a narrow depth range of convection-dominated beat transport, and mild surficial anomalies in fluid {delta}{sup 18}O (max. {delta}{sup 18}O{sub f} = +2%). The shallow temperature gradient reaches a maximum of 130{degrees} C/km, but average convective beat flux at the surface is 11 MW for the entire intrusion. Erosion and lack of appropriate isotopic data for host rocks above the Skaergaard preclude refinement of the geothermal model but this pluton-alteration-calibrated model indicates a much more conduction-dominated cooling history than expected at this site.

  4. A New Method for Intrusion Detection using Manifold Learning Algorithm

    Directory of Open Access Journals (Sweden)

    Guoping Hou

    2013-07-01

    Full Text Available Computer and network security has received and will still receive much attention. Any unexpected intrusion will damage the network. It is therefore imperative to detect the network intrusion to ensure the normal operation of the internet. There are many studies in the intrusion detection and intrusion patter recognition. The artificial neural network (ANN has proven to be powerful for the intrusion detection. However, very little work has discussed the optimization of the input intrusion features for the ANN. Generally, the intrusion features contain a certain number of useless features, which is useless for the intrusion detection. Large dimensions of the feature data will also affect the intrusion detection performance of the ANN. In order to improve the ANN performance, a new approach for network intrusion detection based on nonlinear feature dimension reduction and ANN is proposed in this work. The manifold learning algorithm was used to reduce the intrusion feature vector. Then an ANN classifier was employed to identify the intrusion. The efficiency of the proposed method was evaluated with the real intrusion data. The test result shows that the proposed approach has good intrusion detection performance.

  5. Data Mining and Intrusion Detection Systems

    Directory of Open Access Journals (Sweden)

    Zibusiso Dewa

    2016-01-01

    Full Text Available The rapid evolution of technology and the increased connectivity among its components, imposes new cyber-security challenges. To tackle this growing trend in computer attacks and respond threats, industry professionals and academics are joining forces in order to build Intrusion Detection Systems (IDS that combine high accuracy with low complexity and time efficiency. The present article gives an overview of existing Intrusion Detection Systems (IDS along with their main principles. Also this article argues whether data mining and its core feature which is knowledge discovery can help in creating Data mining based IDSs that can achieve higher accuracy to novel types of intrusion and demonstrate more robust behaviour compared to traditional IDSs.

  6. Intrusion Detection System: Security Monitoring System

    Directory of Open Access Journals (Sweden)

    ShabnamNoorani,

    2015-10-01

    Full Text Available An intrusion detection system (IDS is an ad hoc security solution to protect flawed computer systems. It works like a burglar alarm that goes off if someone tampers with or manages to get past other security mechanisms such as authentication mechanisms and firewalls. An Intrusion Detection System (IDS is a device or a software application that monitors network or system activities for malicious activities or policy violations and produces reports to a management station.Intrusion Detection System (IDS has been used as a vital instrument in defending the network from this malicious or abnormal activity..In this paper we are comparing host based and network based IDS and various types of attacks possible on IDS.

  7. An Adaptive Clustering Algorithm for Intrusion Detection

    Institute of Scientific and Technical Information of China (English)

    QIU Juli

    2007-01-01

    In this paper,we introduce an adaptive clustering algorithm for intrusion detection based on wavecluster which was introduced by Gholamhosein in 1999 and used with success in image processing.Because of the non-stationary characteristic of network traffic,we extend and develop an adaptive wavecluster algorithm for intrusion detection.Using the multiresolution property of wavelet transforms,we can effectively identify arbitrarily shaped clusters at different scales and degrees of detail,moreover,applying wavelet transform removes the noise from the original feature space and make more accurate cluster found.Experimental results on KDD-99 intrusion detection dataset show the efficiency and accuracy of this algorithm.A detection rate above 96% and a false alarm rate below 3% are achieved.

  8. An Overview on Intrusion Detection in Manet

    Directory of Open Access Journals (Sweden)

    Rajesh D. Wagh

    2015-05-01

    Full Text Available A mobile ad hoc network (MANET is a self-configuring of mobile devices network connected without wires and hence MANET has become a very popular technology now days. A MANETS are the networks that are building, when some mobile nodes come in the mobility range of each other for data transfer and communication. In MANET, nodes are not stable hence the communication topology is not stable due to this vulnerable for attacks. MANET devices are connected via wireless links without using an existing network infrastructure or centralized administration due to which MANETs are not able to diverse types of attacks and intrusions. Hence intrusion detection has attracted many researchers. This paper gives an overview and different methods to detect intrusion in MANET.

  9. Promises and risks of Chinese investments in Greenland seen from Nuuk, Copenhagen and Beijing

    DEFF Research Database (Denmark)

    Sørensen, Camilla T. N.

    2017-01-01

    of Chinese investments in Greenland. The analyses draw on interviews and meetings in China and in Copenhagen with Greenlandic, Danish and Chinese researchers, public officials, diplomats and businesses and on statements from Greenlandic, Danish and Chinese governments and politicians....

  10. A Coupled Ocean-Iceberg Model Over The 20th Century: Iceberg Flux At 48°N As A Proxy For Greenland Iceberg Discharge

    Science.gov (United States)

    Bigg, G. R.; Wilton, D.; Hanna, E.

    2013-12-01

    Grant R. Bigg1 , David J. Wilton1 and Edward Hanna1 1Department of Geography, The University of Sheffield, Sheffield, S10 2TN We have used a coupled ocean-iceberg model, the Fine Resolution Greenland and Labrador ocean model [1], to study the variation in, and trajectory of, icebergs over the twentieth century, focusing particularly on Greenland and surrounding areas. The model is forced with daily heat, freshwater and wind fluxes derived from the Twentieth Century Reanalysis Project [2]. We use the observed iceberg flux at 48°N off Newfoundland (I48N) from 1900 to 2008 [3] to assess the iceberg component of the model. Model I48N is calculated with both a variable and constant annual calving rate. The results show that ocean and atmosphere changes alone do not account for the variation in observed I48N and suggests that this series can be used as a proxy for iceberg discharge from west Greenland tidewater glaciers. The implication of this proxy is that there is significant interannual variability in Greenland iceberg discharge over the whole twentieth century. Our model results suggest that in the early decades of the twentieth century I48N was dominated by icebergs originating from south Greenland (below latitude 65°N) with west Greenland becoming the main source of I48N from the late 1930s onwards. Modeled icebergs from the east of Greenland very rarely reach 48°N. We also present results from the ocean model showing the variation of ocean transport fluxes over the course of the twentieth and early twenty first century. References 1. M. R. Wadley, and G. R. Bigg, (2002), Q. J. R. Meteorol. Soc., 128, 2187-2203 2. G. P. Compo, et al. (2011), Q. J. R. Meteorol. Soc., 137, 1-28 3. D. L. Murphy (2011) http://www.navcen.uscg.gov/?pageName=IIPIcebergCounts

  11. An overview to Software Architecture in Intrusion Detection System

    CERN Document Server

    Bahrami, Mehdi

    2012-01-01

    Network intrusion detection systems provide proactive defense against security threats by detecting and blocking attack-related traffic. This task can be highly complex, and therefore, software based network intrusion detection systems have difficulty in handling high speed links. This paper reviews of many type of software architecture in intrusion detection systems and describes the design and implementation of a high-performance network intrusion detection system that combines the use of software-based network intrusion detection sensors and a network processor board. The network processor acts as a customized load balancing splitter that cooperates with a set of modified content-based network intrusion detection sensors in processing network traffic.

  12. Effective analysis of cloud based intrusion detection system

    Directory of Open Access Journals (Sweden)

    Sanjay Ram

    2012-08-01

    Full Text Available The goal of IDS is to analyze events on the network and identify attacks. The increasing number of network security related incidents makes it necessary for organizations to actively protect their sensitive data with the installation of intrusion detection systems (IDS. People are paid more attention on intrusion detection which as an important computer network security technology. According to the development trend of intrusion detection, detecting all kinds of intrusions effectively requires a global view of the monitored network, Here, discuss about new intrusion detection mechanism based on cloud computing, which can make up for the deficiency of traditional intrusion detection, and proved to be great scalable.

  13. Perceived illness intrusion among patients on hemodialysis

    Directory of Open Access Journals (Sweden)

    Bapat Usha

    2009-01-01

    Full Text Available Dialysis therapy is extremely stressful as it interferes with all spheres of daily acti-vities of the patients. This study is aimed at understanding the perceived illness intrusion among pa-tients on hemodialysis (HD and to find the association between illness intrusion and patient demo-graphics as well as duration of dialysis. A cross sectional study involving 90 patients with chronic kidney disease (CKD stage V, on HD was performed during the period from 2005 to 2006. The subjects included were above 18 years of age, willing, stable and on dialysis for at least two months. Patients with psychiatric co-morbidity were excluded. A semi-structured interview schedule covering socio-demographics and a 13 item illness intrusion checklist covering the various aspects of life was ca-rried out. The study patients were asked to rate the illness intrusion and the extent. The data were ana-lyzed statistically. The mean age of the subjects was 50.28 ± 13.69 years, males were predominant (85%, 73% were married, 50% belonged to Hindu religion, 25% had pre-degree education, 25% were employed and 22% were housewives. About 40% and 38% of the study patients belonged to middle and upper socio-economic strata respectively; 86% had urban background and lived in nuclear fami-lies. The mean duration on dialysis was 24 ± 29.6 months. All the subjects reported illness intrusion to a lesser or greater extent in various areas including: health (44%, work (70% finance (55%, diet (50% sexual life (38% and psychological status (25%. Illness had not intruded in areas of rela-tionship with spouse (67%, friends (76%, family (79%, social (40% and religious functions (72%. Statistically significant association was noted between illness intrusion and occupation (P= 0.02.

  14. Topography and Penetration of the Greenland Ice Sheet Measured with Airborne SAR Interferometry

    DEFF Research Database (Denmark)

    Dall, Jørgen; Madsen, Søren Nørvang; Keller, K.

    2001-01-01

    A digital elevation model (DEM) of the Geikie ice sap in East Greenland has been generated from interferometric C-band synthetic aperture radar (SAR) data acquired with the airborne EMISAR system. GPS surveyed radar reflectors and an airborne laser altimeter supplemented the experiment. The accur......A digital elevation model (DEM) of the Geikie ice sap in East Greenland has been generated from interferometric C-band synthetic aperture radar (SAR) data acquired with the airborne EMISAR system. GPS surveyed radar reflectors and an airborne laser altimeter supplemented the experiment....... The accuracy of the SAR DEM is about 1.5 m. The mean difference between the laser heights and the SAR heights changes from 0 m in the soaked zone to a maximum of 13 m in the percolation zone. This is explained by the fact that the snow in the soaked zone contains liquid water which attenuates the radar signals......, while the transparency of the firn in the percolation zone makes volume scattering dominate at the higher elevations. For the first time, the effective penetration has been measured directly as the difference between the interferometric heights and reference heights obtained with GPS and laser altimetry....

  15. A cascade of warming impacts brings bluefin tuna to Greenland waters.

    Science.gov (United States)

    MacKenzie, Brian R; Payne, Mark R; Boje, Jesper; Høyer, Jacob L; Siegstad, Helle

    2014-08-01

    Rising ocean temperatures are causing marine fish species to shift spatial distributions and ranges, and are altering predator-prey dynamics in food webs. Most documented cases of species shifts so far involve relatively small species at lower trophic levels, and consider individual species in ecological isolation from others. Here, we show that a large highly migratory top predator fish species has entered a high latitude subpolar area beyond its usual range. Bluefin tuna, Thunnus thynnus Linnaeus 1758, were captured in waters east of Greenland (65°N) in August 2012 during exploratory fishing for Atlantic mackerel, Scomber scombrus Linnaeus 1758. The bluefin tuna were captured in a single net-haul in 9-11 °C water together with 6 tonnes of mackerel, which is a preferred prey species and itself a new immigrant to the area. Regional temperatures in August 2012 were historically high and contributed to a warming trend since 1985, when temperatures began to rise. The presence of bluefin tuna in this region is likely due to a combination of warm temperatures that are physiologically more tolerable and immigration of an important prey species to the region. We conclude that a cascade of climate change impacts is restructuring the food web in east Greenland waters.

  16. Computationally Efficient Neural Network Intrusion Security Awareness

    Energy Technology Data Exchange (ETDEWEB)

    Todd Vollmer; Milos Manic

    2009-08-01

    An enhanced version of an algorithm to provide anomaly based intrusion detection alerts for cyber security state awareness is detailed. A unique aspect is the training of an error back-propagation neural network with intrusion detection rule features to provide a recognition basis. Network packet details are subsequently provided to the trained network to produce a classification. This leverages rule knowledge sets to produce classifications for anomaly based systems. Several test cases executed on ICMP protocol revealed a 60% identification rate of true positives. This rate matched the previous work, but 70% less memory was used and the run time was reduced to less than 1 second from 37 seconds.

  17. Adaptive Genetic Algorithm Model for Intrusion Detection

    Directory of Open Access Journals (Sweden)

    K. S. Anil Kumar

    2012-09-01

    Full Text Available Intrusion detection systems are intelligent systems designed to identify and prevent the misuse of computer networks and systems. Various approaches to Intrusion Detection are currently being used, but they are relatively ineffective. Thus the emerging network security systems need be part of the life system and this ispossible only by embedding knowledge into the network. The Adaptive Genetic Algorithm Model - IDS comprising of K-Means clustering Algorithm, Genetic Algorithm and Neural Network techniques. Thetechnique is tested using multitude of background knowledge sets in DARPA network traffic datasets.

  18. Intrusion Detection Using Cost-Sensitive Classification

    CERN Document Server

    Mitrokotsa, Aikaterini; Douligeris, Christos

    2008-01-01

    Intrusion Detection is an invaluable part of computer networks defense. An important consideration is the fact that raising false alarms carries a significantly lower cost than not detecting at- tacks. For this reason, we examine how cost-sensitive classification methods can be used in Intrusion Detection systems. The performance of the approach is evaluated under different experimental conditions, cost matrices and different classification models, in terms of expected cost, as well as detection and false alarm rates. We find that even under unfavourable conditions, cost-sensitive classification can improve performance significantly, if only slightly.

  19. Design of Secure Distributed Intrusion Detection Systems

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Intrusion Detection System (IDS) have received a great deal of attention because of their excellent ability of preventing network incidents. Recently, many efficient approaches have been proposed to improve detection ability of IDS. While the self-protection ability of IDS is relatively worse and easy to be exploited by attackers, this paper gives a scheme of Securely Distributed Intrusion Detection System (SDIDS). This system adopts special measurements to enforce the security of IDS components. A new secure mechanism combining role-based access control and attribute certificate is used to resist attack to communication.

  20. Intrusion Detection Approach Using Connectionist Expert System

    Institute of Scientific and Technical Information of China (English)

    MA Rui; LIU Yu-shu; DU Yan-hui

    2005-01-01

    In order to improve the detection efficiency of rule-based expert systems, an intrusion detection approach using connectionist expert system is proposed. The approach converts the AND/OR nodes into the corresponding neurons, adopts the three-layered feed forward network with full interconnection between layers,translates the feature values into the continuous values belong to the interval [0, 1 ], shows the confidence degree about intrusion detection rules using the weight values of the neural networks and makes uncertain inference with sigmoid function. Compared with the rule-based expert system, the neural network expert system improves the inference efficiency.

  1. Intrusion Detection amp Prevention Systems - Sourcefire Snort

    Directory of Open Access Journals (Sweden)

    Rajesh Vuppala

    2015-08-01

    Full Text Available Information security is a challenging issue for all business organizations today amidst increasing cyber threats. While there are many alternative intrusion detection amp prevention systems available to choose from selecting the best solution to implement to detect amp prevent cyber-attacks is a difficult task. The best solution is of the one that gets the best reviews and suits the organizations needs amp budget. In this review paper we summarize various classes of intrusion detection and prevention systems compare features of alternative solutions and make recommendation for implementation of one as the best solution for business organization in Fiji.

  2. Computationally Efficient Neural Network Intrusion Security Awareness

    Energy Technology Data Exchange (ETDEWEB)

    Todd Vollmer; Milos Manic

    2009-08-01

    An enhanced version of an algorithm to provide anomaly based intrusion detection alerts for cyber security state awareness is detailed. A unique aspect is the training of an error back-propagation neural network with intrusion detection rule features to provide a recognition basis. Network packet details are subsequently provided to the trained network to produce a classification. This leverages rule knowledge sets to produce classifications for anomaly based systems. Several test cases executed on ICMP protocol revealed a 60% identification rate of true positives. This rate matched the previous work, but 70% less memory was used and the run time was reduced to less than 1 second from 37 seconds.

  3. Episodes of subsidence and uplift of the conjugate margins of Greenland and Norway after opening of the NE Atlantic

    Science.gov (United States)

    Japsen, Peter; Green, Paul F.; Bonow, Johan M.; Chalmers, James A.

    2016-04-01

    We have undertaken a regional study of the thermo-tectonic development of East Greenland (68-75°N; Bonow et al. 2014; Japsen et al. 2014) and of southern Norway (58-64°N) based on integration of apatite fission-track analysis (AFTA), stratigraphic landscape analysis and the geological record onshore and offshore. Volcanic and sedimentary rocks accumulated on the subsiding, East Greenland margin during and following breakup and then began to be exhumed during late Eocene uplift that preceded a major, early Oligocene plate reorganization in the NE Atlantic. The Norwegian margin also experienced Eocene subsidence and burial; there are hemipelagic, deep-marine sediments of Eocene age along the coast of southern Norway. End-Eocene uplift of the NW European margin led to the formation of a major unconformity along the entire margin and to progradation of clastic wedges from Norway towards the south. Our AFTA data from East Greenland and southern Norway reveal a long history of Mesozoic burial and exhumation across the region, with a number of broadly synchronous events being recorded on both margins. AFTA data from East Greenland show clear evidence for uplift at the Eocene-Oligocene transition whereas the data from Norway do not resolve any effects of exhumation related to this event. AFTA data from the East Greenland margin show evidence of two Neogene events of uplift and incision of the in the late Miocene and Pliocene whereas results from southern Norway define Neogene uplift and erosion which began in the early Miocene. A Pliocene uplift phase in southern Norway is evident from the stratigraphic landscape analysis and from the sedimentary sequences offshore. In East Greenland, a late Eocene phase of uplift led to formation of a regional erosion surface near sea level (the Upper Planation Surface, UPS). Uplift of the UPS in the late Miocene led to formation of the Lower Planation Surface (LPS) by incision below the uplifted UPS, and a Pliocene phase led to

  4. Pliocene retreat of Greenland and Antarctic Ice Sheet margins (Invited)

    Science.gov (United States)

    Deconto, R. M.; Pollard, D.

    2013-12-01

    The middle Pliocene epoch (~3 million years ago) is often considered an analogue for future global climatic conditions, because global mean temperatures were comparable to projections of future climate at the end of this century. Importantly, some estimates of mid-Pliocene sea level are >20 m higher than today, implying the potential for significant retreat of the East Antarctic Ice Sheet (EAIS), in addition to the loss of the Greenland and West Antarctic Ice Sheets (WAIS). Here, we use a hybrid ice sheet-shelf model with freely migrating grounding lines coupled to a high-resolution regional climate model to test the potential for both West and East Antarctic Ice Sheet retreat during the warm Pliocene and in long-term future scenarios with elevated CO2. In these simulations we apply new treatments of i) ice shelf calving (accounting for the effects of divergent ice flow and surface melt water on crevassing), ii) ice-cliff mechanics at the grounding line, iii) improved sub-glacial bathymetry using BEDMAP2, and iv) a range of plausible ocean warming scenarios based on offline ocean modeling. In warm Pliocene simulations, the combination of improved bathymetric detail and more physically based model treatments of floating and grounded calving fronts substantially increases the rates and magnitudes of ice sheet retreat into over-deepened subglacial basins in both in West and East Antarctica. These new results imply the EAIS margin did indeed contribute to elevated (and orbitally paced) Pliocene sea levels, with Antarctica contributing up to ~20m equivalent sea level during the warmest intervals. In long-term (10^3-4-yr) future simulations using the same model physics, we find these new mechanisms produce a much more sensitive and vulnerable ice sheet than previously considered, with the potential for substantial future retreat of both WAIS and parts of the East Antarctic margin in response to the combined effects of increased surface melt on ice shelf surfaces and

  5. The intercultural challenges of engineering education in a Greenlandic context

    DEFF Research Database (Denmark)

    Hendriksen, Kåre; Christensen, Hans Peter

    2014-01-01

    for this program: to educate professionals with a deep understanding of the Arctic, and to give the Greenlandic youth a better chance of getting a higher education. To align the teaching philosophy with the Greenlandic students’ cultural background, the curriculum structure has large interdisciplinary courses...... at an abstract level. Additionally, the group work and the class teaching are challenging due to the culturally -based reticence and conflict -averse nature of many of the Greenlandic students, which gives the Danish students a dominant position. This often creates a negative spiral, where many Greenlandic...... based on authentic local cases and intercultural group work. This paper will focus on the challenges caused by many of the Greenlandic students’ weak academic preparation, and the fact that the cultural background embedded in the Greenlandic language can make it very difficult to comprehend topics...

  6. The Greenland Sea Odden: Intra- and inter-annual variability

    Science.gov (United States)

    Russell, C.A.; Fischer, K.W.; Shuchman, R.A.; Josberger, E.G.

    1997-01-01

    The "Odden" is a large sea ice feature that forms in the East Greenland Sea which generally forms at the beginning of the winter season and can cover 300,000 km2. Throughout the winter, the outer edge of the Odden may advance and retreat by several hundred kilometers on time scales of a few days to weeks. Satellite passive microwave observations from 1978 through 1995 provide a continuous record of the spatial and temporal variations of this extremely dynamic phenomenon. The 17 year record shows both strong inter- and intra-annual variations in Odden extent and temporal behavior. An analysis of the satellite passive microwave derived ice area and extent time series along with meteorological data from the Arctic Drifting Buoy Network determined the meteorological forcing required for Odden growth, maintenance and decay. The key meteorological parameters which cause the rapid ice formation and decay associated with the Odden are, in order of importance, air temperature, wind speed, and wind direction. Atmospheric pressure was found not to play a significant role in the Odden events. Air temperature and wind direction are the dominant variables with temperatures below -9.5??C and winds from the west required to trigger significant Odden ice formation events. ??2004 Copyright SPIE - The International Society for Optical Engineering.

  7. Greenland ice sheet motion insensitive to exceptional meltwater forcing

    OpenAIRE

    Tedstone, Andrew J.; P. W. Nienow; A. J. Sole; D. W. F. Mair; Cowton, Tom; I. D. Bartholomew; King, M. A.

    2013-01-01

    Changes to the dynamics of the Greenland ice sheet can be forced by various mechanisms including surface-melt-induced ice acceleration and oceanic forcing of marine-terminating glaciers. We use observations of ice motion to examine the surface melt-induced dynamic response of a land-terminating outlet glacier in south-west Greenland to the exceptional melting observed in 2012. During summer, meltwater generated on the Greenland Ice Sheet (GrIS) surface accesses the ice sheet bed, lubricating ...

  8. Monitoring natural vegetation in Southern Greenland using NOAA AVHRR and field measurements

    DEFF Research Database (Denmark)

    Hansen, Birger Ulf

    1991-01-01

    vegetation, sheep farming, biomass production, Remote Sensing, NOAA AVHRR, Southern Greenland, NDVI......vegetation, sheep farming, biomass production, Remote Sensing, NOAA AVHRR, Southern Greenland, NDVI...

  9. Overview of coralline red algal crusts and rhodolith beds (Corallinales, Rhodophyta) and their possible ecological importance in Greenland

    DEFF Research Database (Denmark)

    Jørgensbye, Helle; Halfar, Jochen

    2016-01-01

    Coralline red algae are a globally distributed and abundant group of shallow marine benthic calcifiers. They can form important ecosystems that provide a three-dimensional habitat to a large variety of marine organisms. While the study of coralline red algae has traditionally been focused on warm......-water habitats, numerous recent reports have now described widespread coralline red algal ecosystems from high-latitude regions, particularly in the Northern Hemisphere. In fact, it is becoming increasingly evident that coralline red algae are likely the dominant marine calcifying organisms on the seafloor...... of the Arctic and subarctic photic zone. This article gives a first overview of the distribution of coralline red algal crusts and rhodolith (free-living coralline red algal nodules) grounds in Greenland and the first report of rhodoliths in East Greenland. Museum data and recent sampling information have been...

  10. Mass loss from the southern half of the Greenland Ice Sheet since the Little Ice Age Maximum

    DEFF Research Database (Denmark)

    Kjeldsen, Kristian Kjellerup; Kjær, Kurt H.; Bjørk, Anders Anker

    Northern hemisphere temperatures reached their Holocene minimum and most glaciers reached their maximum during The Little Ice Age (LIA), but the timing of specific cold intervals is site-specific. In southern Greenland, we have compiled data from organic matter incorporated in LIA sediments, used...... as a signal for ice-free terrain being overridden by LIA glacier advances, and data from threshold lakes showing the onset of glacier-fed lakes, thus revealing the advance-maximum phase initiating the LIA. Finally, we have compiled lichenometry results indicating the onset of bedrock vegetation succeeding ice...... the Arctic. Furthermore, the glacier response seems to be mirrored by a oceanic cooling between 500-1000 AD, followed by onset of the LIA at 1150-1250 AD as seen in the relative strength of warm subsurface water and the influence of the East Greenland Current....

  11. Building sustained partnerships in Greenland through shared science

    Science.gov (United States)

    Culler, L. E.; Albert, M. R.; Ayres, M. P.; Grenoble, L. A.; Virginia, R. A.

    2013-12-01

    Greenland is a hotspot for polar environmental change research due to rapidly changing physical and ecological conditions. Hundreds of international scientists visit the island each year to carry out research on diverse topics ranging from atmospheric chemistry to ice sheet dynamics to Arctic ecology. Despite the strong links between scientific, social, and political issues of rapid environmental change in Greenland, communication with residents of Greenland is often neglected by researchers. Reasons include language barriers, difficulties identifying pathways for communication, balancing research and outreach with limited resources, and limited social and cultural knowledge about Greenland by scientists. Dartmouth College has a legacy of work in the Polar Regions. In recent years, a National Science Foundation (NSF) Integrative Graduate Education and Research Traineeship (IGERT) in Polar Environmental Change funded training for 25 Ph.D. students in the Ecology, Earth Science, and Engineering graduate programs at Dartmouth. An overarching goal of this program is science communication between these disciplines and to diverse audiences, including communicating about rapid environmental change with students, residents, and the government of Greenland. Students and faculty in IGERT have been involved in the process of engaging with and sustaining partnerships in Greenland that support shared cultural and educational experiences. We have done this in three ways. First, a key component of our program has been hosting students from Ilisimatusarfik (the University of Greenland). Since 2009, five Greenlandic students have come to Dartmouth and formed personal connections with Dartmouth students while introducing their Greenlandic culture and language (Kalaallisut). Second, we have used our resources to extend our visits to Greenland, which has allowed time to engage with the community in several ways, including sharing our science via oral and poster presentations at Katuaq

  12. Vitamins and minerals in the traditional Greenland diet

    DEFF Research Database (Denmark)

    Andersen, S. M.

    The relative importance of traditional Greenlandic food items has diminished during the last decades. Today these account for 25% of the Greenland diet with a dominance of fish, seabirds, and marine mammals. This report synthesises the available information on concentrations of vitamins...... and minerals in the various food items that form the traditional Greenlandic diet. However, through this diet people in Greenland are also exposed to a high intake of heavy metals and organochlorines, due to a contamination of many of these food items. In combination with information on the concentration...

  13. Data Mining Approaches for Intrusion Detection

    Science.gov (United States)

    2007-11-02

    In this paper we discuss our research in developing general and systematic methods for intrusion detection. The key ideas are to use data mining techniques...two general data mining algorithms that we have implemented: the association rules algorithm and the frequent episodes algorithm. These algorithms can

  14. Intrusion Detection System Visualization of Network Alerts

    Science.gov (United States)

    2010-07-01

    Intrusion Detection System Visualization of Network Alerts Dolores M. Zage and Wayne M. Zage Ball State University Final Report July 2010...contracts. Staff Wayne Zage, Director of the S2ERC and Professor, Department of Computer Science, Ball State University Dolores Zage, Research

  15. Chemical Observations of a Polar Vortex Intrusion

    Science.gov (United States)

    Schoeberl, M. R.; Kawa, S. R.; Douglass, A. R.; McGee, T. J.; Browell, E.; Waters, J.; Livesey, N.; Read, W.; Froidevaux, L.

    2006-01-01

    An intrusion of vortex edge air in D the interior of the Arctic polar vortex was observed on the January 31,2005 flight of the NASA DC-8 aircraft. This intrusion was identified as anomalously high values of ozone by the AROTAL and DIAL lidars. Our analysis shows that this intrusion formed when a blocking feature near Iceland collapsed, allowing edge air to sweep into the vortex interior. along the DC-8 flight track also shows the intrusion in both ozone and HNO3. Polar Stratospheric Clouds (PSCs) were observed by the DIAL lidar on the DC-8. The spatial variability of the PSCs can be explained using MLS HNO3 and H2O observations and meteorological analysis temperatures. We also estimate vortex denitrification using the relationship between N2O and HNO3. Reverse domain fill back trajectory calculations are used to focus on the features in the MLS data. The trajectory results improve the agreement between lidar measured ozone and MLS ozone and also improve the agreement between the HNO3 measurements PSC locations. The back trajectory calculations allow us to compute the local denitrification rate and reduction of HCl within the filament. We estimate a denitrification rate of about lO%/day after exposure to below PSC formation temperature. Analysis of Aura MLS observations made

  16. Root resorption after orthodontic intrusion and extrusion:.

    NARCIS (Netherlands)

    Han, G.; Huang, S.; Hoff, J.W. Von den; Zeng, X.; Kuijpers-Jagtman, A.M.

    2005-01-01

    The aim of this investigation was to compare root resorption in the same individual after application of continuous intrusive and extrusive forces. In nine patients (mean age 15.3 years), the maxillary first premolars were randomly intruded or extruded with a continuous force of 100 cN for eight wee

  17. Access Control from an Intrusion Detection Perspective

    NARCIS (Netherlands)

    Nunes Leal Franqueira, V.

    Access control and intrusion detection are essential components for securing an organization's information assets. In practice, these components are used in isolation, while their fusion would contribute to increase the range and accuracy of both. One approach to accomplish this fusion is the

  18. Characterization of household waste in Greenland

    DEFF Research Database (Denmark)

    Eisted, Rasmus; Christensen, Thomas Højlund

    2011-01-01

    The composition of household waste in Greenland was investigated for the first time. About 2tonnes of household waste was sampled as every 7th bag collected during 1week along the scheduled collection routes in Sisimiut, the second largest town in Greenland with about 5400 inhabitants....... The collection bags were sorted manually into 10 material fractions. The household waste composition consisted primarily of biowaste (43%) and the combustible fraction (30%), including anything combustible that did not belong to other clean fractions as paper, cardboard and plastic. Paper (8%) (dominated...... by magazine type paper) and glass (7%) were other important material fractions of the household waste. The remaining approximately 10% constituted of steel (1.5%), aluminum (0.5%), plastic (2.4%), wood (1.0%), non-combustible waste (1.8%) and household hazardous waste (1.2%). The high content of biowaste...

  19. Secret Science: Exploring Cold War Greenland

    Science.gov (United States)

    Harper, K.

    2013-12-01

    During the early Cold War - from the immediate postwar period through the 1960s - the United States military carried out extensive scientific studies and pursued technological developments in Greenland. With few exceptions, most of these were classified - sometimes because new scientific knowledge was born classified, but mostly because the reasons behind the scientific explorations were. Meteorological and climatological, ionospheric, glaciological, seismological, and geological studies were among the geophysical undertakings carried out by military and civilian scientists--some in collaboration with the Danish government, and some carried out without their knowledge. This poster will present some of the results of the Exploring Greenland Project that is coming to a conclusion at Denmark's Aarhus University.

  20. Resilience and Renewable Energy Planning in Greenland

    DEFF Research Database (Denmark)

    Carruth, Susan

    2014-01-01

    , and the transition to a renewable energy system is proving no exception. Such a transition is particularly amplified in the context of Greenland – a country undergoing rapid transformation in many fields, including energy. Resilience theory offers an approach for how to plan for this energy transition, but how...... to translate resilience theory into planning practices remains underdeveloped. The paper begins by outlining some of the challenges in planning a transition to renewable energy, and sketching Greenland’s energy landscape. It then discusses the key characteristics of resilience thinking, before proposing......Using a combination of thematic analysis and studio-based planning proposals in West Greenland, this paper proposes that there is more than one interpretation of resilience in renewable energy planning. All energy transitions, from one system to another, are protracted and unpredictable...

  1. Early life of inshore fishes in Greenland

    DEFF Research Database (Denmark)

    Swalethorp, Rasmus

    regimes, relative inflowof Atlantic water, temperature increase, glacial melting and runoff from land, the environment off West Greenland will undergo significant changes in the future. This thesis points out that in fjord systems, where such processes might change the timing and magnitude of freshwater....... The distribution of larvae generally overlapped the distribution of their preferred prey. Although no direct relationship could be found between prey availability and cod larval growth, the otolith growth rate was significantly improved in larvae that dispersing away from the spawning area. This was despite lower...... Greenlandic Godthåbsfjord system and the offshore Fyllas Bank, which encompass different oceanographic regimes, and which harbor different zooplanktoncommunities in specific regions. Significantly different patterns of distribution were shown for the fish larvae and these appeared linked to the specific...

  2. Resilience and Renewable Energy Planning in Greenland

    DEFF Research Database (Denmark)

    Carruth, Susan

    2014-01-01

    Using a combination of thematic analysis and studio-based planning proposals in West Greenland, this paper proposes that there is more than one interpretation of resilience in renewable energy planning. All energy transitions, from one system to another, are protracted and unpredictable......, and the transition to a renewable energy system is proving no exception. Such a transition is particularly amplified in the context of Greenland – a country undergoing rapid transformation in many fields, including energy. Resilience theory offers an approach for how to plan for this energy transition, but how...... to translate resilience theory into planning practices remains underdeveloped. The paper begins by outlining some of the challenges in planning a transition to renewable energy, and sketching Greenland’s energy landscape. It then discusses the key characteristics of resilience thinking, before proposing...

  3. Complex Greenland outlet glacier flow captured

    Science.gov (United States)

    Aschwanden, Andy; Fahnestock, Mark A.; Truffer, Martin

    2016-02-01

    The Greenland Ice Sheet is losing mass at an accelerating rate due to increased surface melt and flow acceleration in outlet glaciers. Quantifying future dynamic contributions to sea level requires accurate portrayal of outlet glaciers in ice sheet simulations, but to date poor knowledge of subglacial topography and limited model resolution have prevented reproduction of complex spatial patterns of outlet flow. Here we combine a high-resolution ice-sheet model coupled to uniformly applied models of subglacial hydrology and basal sliding, and a new subglacial topography data set to simulate the flow of the Greenland Ice Sheet. Flow patterns of many outlet glaciers are well captured, illustrating fundamental commonalities in outlet glacier flow and highlighting the importance of efforts to map subglacial topography. Success in reproducing present day flow patterns shows the potential for prognostic modelling of ice sheets without the need for spatially varying parameters with uncertain time evolution.

  4. Uncertainty in Greenland glacial isostatic adjustment

    DEFF Research Database (Denmark)

    Milne, G. A.; Lecavalier, B.; Kjeldsen, K. K.

    It is well known that the interpretation of geodetic data in Greenland to constrain recent ice mass changes requires knowledge of isostatic land motion associated with past changes in the ice sheet. In this talk we will consider a variety of factors that limit how well the signal due to past mass...... changes (commonly referred to as glacial isostatic adjustment (GIA)) can be defined. Predictions based on a new model of Greenland GIA will be shown. Using these predictions as a reference, we will consider the influence of plausible variations in some key aspects of both the Earth and ice load components...... of the GIA model on predictions of land motion and gravity changes. The sensitivity of model output to plausible variations in both depth-dependent and lateral viscosity structure will be considered. With respect to the ice model, we will compare the relative contributions of loading during key periods...

  5. How stratospheric are deep stratospheric intrusions?

    Science.gov (United States)

    Trickl, T.; Vogelmann, H.; Giehl, H.; Scheel, H.-E.; Sprenger, M.; Stohl, A.

    2014-09-01

    Preliminary attempts of quantifying the stratospheric ozone contribution in the observations at the Zugspitze summit (2962 m a.s.l.) next to Garmisch-Partenkirchen in the German Alps had yielded an approximate doubling of the stratospheric fraction of the Zugspitze ozone during the time period 1978 to 2004. These investigations had been based on data filtering by using low relative humidity (RH) and elevated 7Be as the criteria for selecting half-hour intervals of ozone data representative of stratospheric intrusion air. To quantify the residual stratospheric component in stratospherically influenced air masses, however, the mixing of tropospheric air into the stratospheric intrusion layers must be taken into account. In fact, the dewpoint mirror instrument at the Zugspitze summit station rarely registers RH values lower than 10% in stratospheric air intrusions. Since 2007 a programme of routine lidar sounding of ozone, water vapour and aerosol has been conducted in the Garmisch-Partenkirchen area. The lidar results demonstrate that the intrusion layers are drier by roughly one order of magnitude than indicated in the in situ measurements. Even in thin layers RH values clearly below 1% have frequently been observed. These thin, undiluted layers present an important challenge for atmospheric modelling. Although the ozone values never reach values typical of the lower-stratosphere it becomes, thus, obvious that, without strong wind shear or convective processes, mixing of stratospheric and tropospheric air must be very slow in most of the free troposphere. As a consequence, the analysis the Zugspitze data can be assumed to be more reliable than anticipated. Finally, the concentrations of Zugspitze carbon monoxide rarely drop inside intrusion layers and normally stay clearly above full stratospheric values. This indicates that most of the CO, and thus the intrusion air mass, originates in the shallow "mixing layer" around the thermal tropopause. The CO mixing ratio in

  6. How stratospheric are deep stratospheric intrusions?

    Directory of Open Access Journals (Sweden)

    T. Trickl

    2014-06-01

    Full Text Available Preliminary attempts of quantifying the stratospheric ozone contribution in the observations at the Zugspitze summit (2962 m a.s.l. next to Garmisch-Partenkirchen in the German Alps had yielded an approximate doubling of the stratospheric fraction of the Zugspitze ozone during the time period 1978 and 2004. These investigations had been based on data filtering by using low relative humidity and elevated 7Be as the criteria for selecting half-hour intervals of ozone data representative of stratospheric intrusion air. For quantifying the residual stratospheric component in stratospherically influenced air masses, however, the mixing of tropospheric air into the stratospheric intrusion layers must be taken into account. In fact, the dew-point-mirror instrument at the Zugspitze summit station rarely registers relative humidity (RH values lower than 10% in stratospheric air intrusions. Since 2007 a programme of routine lidar sounding of ozone, water vapour and aerosol has been conducted in the Garmisch-Partenkirchen area. The lidar results demonstrate that the intrusion layers are dryer by roughly one order of magnitude than indicated in the in-situ measurements. Even in thin layers frequently RH values clearly below 1% have been observed. These thin, undiluted layers present an important challenge for atmospheric modelling. Although the ozone values never reach values typical of the lower-stratosphere it becomes, thus, obvious that, without strong wind shear or convective processes, mixing of stratospheric and tropospheric air must be very slow in most of the free troposphere. As a consequence, the analysis the Zugspitze data can be assumed to be more reliable than anticipated. Finally, the concentrations of Zugspitze carbon monoxide rarely drop inside intrusion layers and normally stay clearly above full stratospheric values. This indicates that most of the CO and, thus, the intrusion air mass originate in the shallow "mixing layer" around the

  7. How stratospheric are deep stratospheric intrusions?

    Directory of Open Access Journals (Sweden)

    T. Trickl

    2014-09-01

    Full Text Available Preliminary attempts of quantifying the stratospheric ozone contribution in the observations at the Zugspitze summit (2962 m a.s.l. next to Garmisch-Partenkirchen in the German Alps had yielded an approximate doubling of the stratospheric fraction of the Zugspitze ozone during the time period 1978 to 2004. These investigations had been based on data filtering by using low relative humidity (RH and elevated 7Be as the criteria for selecting half-hour intervals of ozone data representative of stratospheric intrusion air. To quantify the residual stratospheric component in stratospherically influenced air masses, however, the mixing of tropospheric air into the stratospheric intrusion layers must be taken into account. In fact, the dewpoint mirror instrument at the Zugspitze summit station rarely registers RH values lower than 10% in stratospheric air intrusions. Since 2007 a programme of routine lidar sounding of ozone, water vapour and aerosol has been conducted in the Garmisch-Partenkirchen area. The lidar results demonstrate that the intrusion layers are drier by roughly one order of magnitude than indicated in the in situ measurements. Even in thin layers RH values clearly below 1% have frequently been observed. These thin, undiluted layers present an important challenge for atmospheric modelling. Although the ozone values never reach values typical of the lower-stratosphere it becomes, thus, obvious that, without strong wind shear or convective processes, mixing of stratospheric and tropospheric air must be very slow in most of the free troposphere. As a consequence, the analysis the Zugspitze data can be assumed to be more reliable than anticipated. Finally, the concentrations of Zugspitze carbon monoxide rarely drop inside intrusion layers and normally stay clearly above full stratospheric values. This indicates that most of the CO, and thus the intrusion air mass, originates in the shallow "mixing layer" around the thermal tropopause. The

  8. A world without Greenland: impacts on the Northern Hemisphere winter circulation in low- and high-resolution models

    Science.gov (United States)

    Junge, M. M.; Blender, R.; Fraedrich, K.; Gayler, V.; Luksch, U.; Lunkeit, F.

    2005-02-01

    To investigate the effect of Greenland’s orography on the northern hemisphere winter circulation experiments with an atmospheric GCM are conducted: a perturbed integration where standard orography is reduced to sea level in the Greenland area is compared to a standard orography control integration. The outcome of these experiments suggests that the existence of high mountains at Greenland causes a reinforcement of the stationary wave field in the Atlantic sector, colder temperatures to the west of Greenland and warmer temperatures to the east and south, over the North Atlantic. The impact on the flow field cannot be understood in the framework of standing Rossby waves, but it indicates a resonance between remotely forced stationary waves and local (thermo-) dynamics. The pattern of the North Atlantic Oscillation (NAO), in particular the northern centre, lies further to the east in the flat-Greenland experiment compared to the control run and the observations. Together with the fact that the climatological low-pressure system around Iceland hardly shifts, this suggests that the location of the NAO is not necessarily tied to the time mean pressure distributions. Considering the model resolution as a parameter, experiments with a high resolution (T106) suggest that the near-field changes are represented sufficiently by a T42 resolution, a standard resolution used in state-of-the-art coupled climate models. In contrast, far-field changes depend critically on model resolution. Hemispheric circulation and temperature changes differ substantially from low to high resolution, and generalized statements about the impact of Greenland’s orography cannot be made.

  9. NADIR (Network Anomaly Detection and Intrusion Reporter): A prototype network intrusion detection system

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, K.A.; DuBois, D.H.; Stallings, C.A.

    1990-01-01

    The Network Anomaly Detection and Intrusion Reporter (NADIR) is an expert system which is intended to provide real-time security auditing for intrusion and misuse detection at Los Alamos National Laboratory's Integrated Computing Network (ICN). It is based on three basic assumptions: that statistical analysis of computer system and user activities may be used to characterize normal system and user behavior, and that given the resulting statistical profiles, behavior which deviates beyond certain bounds can be detected, that expert system techniques can be applied to security auditing and intrusion detection, and that successful intrusion detection may take place while monitoring a limited set of network activities such as user authentication and access control, file movement and storage, and job scheduling. NADIR has been developed to employ these basic concepts while monitoring the audited activities of more than 8000 ICN users.

  10. Simulation of network intrusion detection system with GPenSim

    OpenAIRE

    2011-01-01

    In recent years, network has penetrated into every aspect of our life with its rapid growth and popularization. More and more serious network security problems have occurred together with this process, especially network intrusion problem. It has seriously affected the normal use of network, so research of network intrusion detection has become one of the hottest research areas. This thesis simulated a network intrusion detection system based on particle filter to solve the network intrusion ...

  11. Towards Multi-Stage Intrusion Detection using IP Flow Records

    OpenAIRE

    Muhammad Fahad Umer; Muhammad Sher; Imran Khan

    2016-01-01

    Traditional network-based intrusion detection sys-tems using deep packet inspection are not feasible for modern high-speed networks due to slow processing and inability to read encrypted packet content. As an alternative to packet-based intrusion detection, researchers have focused on flow-based intrusion detection techniques. Flow-based intrusion detection systems analyze IP flow records for attack detection. IP flow records contain summarized traffic information. However, flow data is very ...

  12. Efficiency of Svm and Pca to Enhance Intrusion Detection System

    OpenAIRE

    Soukaena Hassan Hashem

    2013-01-01

    Intrusion detection system (IDS) is a system that gathers and analyzes information from various areas within a computer or a network to identify attacks made against these components. This research proposed an Intrusion Detection Model (IDM) for detection intrusion attempts, the proposal is a hybrid IDM because it considers both features of network packets and host features that are sensitive to most intrusions. The dataset used to build the hybrid IDM is the proposed HybD (Hybrid Dataset) da...

  13. Snow Drift Management: Summit Station Greenland

    Science.gov (United States)

    2016-05-01

    ER D C/ CR RE L TR -1 6- 6 Engineering for Polar Operations, Logistics, and Research (EPOLAR) Snow Drift Management Summit Station...Drift Management Summit Station Greenland Robert B. Haehnel and Matthew F. Bigl U.S. Army Engineer Research and Development Center (ERDC) Cold...Engineering for Polar Operations, Logistics, and Research (EPOLAR) EP-ARC-15-33, “Monitoring and Managing Snow Drifting at Summit Station, Greenland” ERDC

  14. Studying health in Greenland: Obligations and challenges

    DEFF Research Database (Denmark)

    Bjerregaard, Peter; Mulvad, Gert; Olsen, Jørn

    2003-01-01

    rapid epidemiological transition carries prospects of global significance. The Inuit are a genetically distinct people living under extreme physical conditions. Their traditional living conditions and diet are currently undergoing a transformation, which may approach their disease pattern...... to that of the industrialized world, while still including local outbreaks of tuberculosis. Health research in Greenland is logistically difficult and costly, but offers opportunities not found elsewhere in the world. A long tradition of registration enhances the possibilities for research. A number of research institutions...

  15. Generating synthetic fjord bathymetry for coastal Greenland

    Science.gov (United States)

    Williams, Christopher N.; Cornford, Stephen L.; Jordan, Thomas M.; Dowdeswell, Julian A.; Siegert, Martin J.; Clark, Christopher D.; Swift, Darrel A.; Sole, Andrew; Fenty, Ian; Bamber, Jonathan L.

    2017-02-01

    Bed topography is a critical boundary for the numerical modelling of ice sheets and ice-ocean interactions. A persistent issue with existing topography products for the bed of the Greenland Ice Sheet and surrounding sea floor is the poor representation of coastal bathymetry, especially in regions of floating ice and near the grounding line. Sparse data coverage, and the resultant coarse resolution at the ice-ocean boundary, poses issues in our ability to model ice flow advance and retreat from the present position. In addition, as fjord bathymetry is known to exert strong control on ocean circulation and ice-ocean forcing, the lack of bed data leads to an inability to model these processes adequately. Since the release of the last complete Greenland bed topography-bathymetry product, new observational bathymetry data have become available. These data can be used to constrain bathymetry, but many fjords remain completely unsampled and therefore poorly resolved. Here, as part of the development of the next generation of Greenland bed topography products, we present a new method for constraining the bathymetry of fjord systems in regions where data coverage is sparse. For these cases, we generate synthetic fjord geometries using a method conditioned by surveys of terrestrial glacial valleys as well as existing sinuous feature interpolation schemes. Our approach enables the capture of the general bathymetry profile of a fjord in north-west Greenland close to Cape York, when compared to observational data. We validate our synthetic approach by demonstrating reduced overestimation of depths compared to past attempts to constrain fjord bathymetry. We also present an analysis of the spectral characteristics of fjord centrelines using recently acquired bathymetric observations, demonstrating how a stochastic model of fjord bathymetry could be parameterised and used to create different realisations.

  16. Experience with cochlear implants in Greenlanders with profound hearing loss living in Greenland

    DEFF Research Database (Denmark)

    Homøe, Preben; Andersen, Ture; Grøntved, Aksel

    2013-01-01

    intervention. The logistics and lack of availability of speech therapists in Greenland hampers possibilities for optimal language and speech therapy of CI patients in Greenland. This study aims at describing the results of CI treatment in Greenlanders and the outcome of the CI operations along......OBJECTIVE: Cochlear implant (CI) treatment was introduced to the world in the 1980s and has become a routine treatment for congenital or acquired severe-to-profound hearing loss. CI treatment requires access to a highly skilled team of ear, nose and throat specialists, audiologists and speech...... auditory and speech training. Six children attend mainstream public school while one child is in kindergarten. Of the adults, only 1 has achieved good speech perception with full-time use of CI while 3 do not use the CI. DISCUSSION: From an epidemiological point of view, approximately 1-3 children below 6...

  17. Subannual layer variability in Greenland firn cores

    Science.gov (United States)

    Kjær, Helle Astrid; Vallelonga, Paul; Vinther, Bo; Winstrup, Mai; Simonsen, Marius; Maffezzoli, Niccoló; Jensen, Camilla Marie

    2017-04-01

    Ice cores are used to infer information about the past and modern techniques allow for high resolution (CFA) of the ice. Such analysis is often used to inform on annual layers to constrain dating of ice cores, but can also be extended to provide information on sub-annual deposition patterns. In this study we use available high resolution data from multiple shallow cores around Greenland to investigate the seasonality and trends in the most often continuously measured components sodium, insoluble dust, calcium, ammonium and conductivity (or acidity) from 1800 AD to today. We evaluate the similarities and differences between the records and discuss the causes from different sources and transport to deposition and post-deposition effects over differences in measurement set up. Further we add to the array of cores already published with measurements from the newly drilled ReCAP ice core from a coastal ice cap in eastern Greenland and from a shallow core drilled at the high accumulation site at the Greenland South Dome.

  18. Resilience and Renewable Energy Planning in Greenland

    DEFF Research Database (Denmark)

    Carruth, Susan

    2014-01-01

    Using a combination of thematic analysis and studio-based planning proposals in West Greenland, this paper proposes that there is more than one interpretation of resilience in renewable energy planning. All energy transitions, from one system to another, are protracted and unpredictable, and the ......Using a combination of thematic analysis and studio-based planning proposals in West Greenland, this paper proposes that there is more than one interpretation of resilience in renewable energy planning. All energy transitions, from one system to another, are protracted and unpredictable......, and the transition to a renewable energy system is proving no exception. Such a transition is particularly amplified in the context of Greenland – a country undergoing rapid transformation in many fields, including energy. Resilience theory offers an approach for how to plan for this energy transition, but how...... to translate resilience theory into planning practices remains underdeveloped. The paper begins by outlining some of the challenges in planning a transition to renewable energy, and sketching Greenland’s energy landscape. It then discusses the key characteristics of resilience thinking, before proposing...

  19. Uncertainty in Greenland glacial isostatic adjustment (Invited)

    Science.gov (United States)

    Milne, G. A.; Lecavalier, B.; Kjeldsen, K. K.; Kjaer, K.; Wolstencroft, M.; Wake, L. M.; Simpson, M. J.; Long, A. J.; Woodroffe, S.; Korsgaard, N. J.; Bjork, A. A.; Khan, S. A.

    2013-12-01

    It is well known that the interpretation of geodetic data in Greenland to constrain recent ice mass changes requires knowledge of isostatic land motion associated with past changes in the ice sheet. In this talk we will consider a variety of factors that limit how well the signal due to past mass changes (commonly referred to as glacial isostatic adjustment (GIA)) can be defined. Predictions based on a new model of Greenland GIA will be shown. Using these predictions as a reference, we will consider the influence of plausible variations in some key aspects of both the Earth and ice load components of the GIA model on predictions of land motion and gravity changes. The sensitivity of model output to plausible variations in both depth-dependent and lateral viscosity structure will be considered. With respect to the ice model, we will compare the relative contributions of loading during key periods of the ice history with a focus on the past few thousand years. In particular, we will show predictions of contemporary land motion and gravity changes due to loading changes following the Little Ice Age computed using a new reconstruction of ice thickness changes based largely on empirical data. A primary contribution of this work will be the identification of dominant sources of uncertainty in current models of Greenland GIA and the regions most significantly affected by this uncertainty.

  20. Coal facies studies in Denmark and Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Henrik I. [Geological Survey of Denmark and Greenland (GEUS), Department of Reservoir Geology, Oester Voldgade 10, DK-1350 Copenhagen K (Denmark)

    2004-04-23

    Coal of Jurassic age occurs onshore Denmark and in the Danish North Sea, whereas coal of Carboniferous and Miocene age only occurs in the Danish North Sea and onshore Denmark, respectively. The Lower-Middle Jurassic coals are the most widespread and best documented. Onshore Denmark the coals are of low rank while the Jurassic coals in the North Sea are thermally mature and hydrocarbon generating in the Soegne Basin. The Jurassic coals have a maximum thickness of similar2 m and were formed in coastal plain mires and in inland fresh water mires. The Miocene brown coals, up to similar2 m thick, were formed in an overall deltaic setting. Lower Carboniferous and Palaeogene coals occur in northern Greenland, Middle Jurassic coals in northeast Greenland, and Cretaceous coals in western Greenland. The Middle Jurassic low rank coals have been investigated in detail. The up to similar3.5-m-thick coal seams accumulated in coastal mires and they may have an extraordinary resinite-enriched composition. Only a single Cretaceous coal seam has been investigated with regard to the depositional environment; the seam records drowning of a peat mire. The Lower Carboniferous and Palaeogene coals have not been investigated.

  1. Experience with cochlear implants in Greenlanders with profound hearing loss living in Greenland

    Directory of Open Access Journals (Sweden)

    Preben Homøe

    2013-08-01

    Full Text Available Objective. Cochlear implant (CI treatment was introduced to the world in the 1980s and has become a routine treatment for congenital or acquired severe-to-profound hearing loss. CI treatment requires access to a highly skilled team of ear, nose and throat specialists, audiologists and speech-language pathologists for evaluation, surgery and rehabilitation. In particular, children treated with CI are in need of long-term post-operative auditory training and other follow-up support. Design. The study is retrospective with updated information on present performance. Results. Since 2001, a total of 11 Greenlandic patients living in Greenland have been treated with CI, 7 children and 4 adults. Of these children, 4 use oral communication only and are full-time CI-users, 2 with full-time use of CI are still in progress with use of oral communication, and 1 has not acquired oral language yet, but has started auditory and speech training. Six children attend mainstream public school while one child is in kindergarten. Of the adults, only 1 has achieved good speech perception with full-time use of CI while 3 do not use the CI. Discussion. From an epidemiological point of view, approximately 1–3 children below 6 years are in need of a CI every second year in Greenland often due to sequelae from meningitis, which may cause postinfectious deafness. Screening of new-borns for hearing has been started in Greenland establishing the basis for early diagnosis of congenital hearing impairment and subsequent intervention. The logistics and lack of availability of speech therapists in Greenland hampers possibilities for optimal language and speech therapy of CI patients in Greenland. This study aims at describing the results of CI treatment in Greenlanders and the outcome of the CI operations along with the auditory and speech/language outcomes. Finally, we present a suggestion for the future CI treatment and recommendations for an increased effort in the

  2. Geologic setting, depths of emplacement, and regional distribution of fluid inclusions in intrusions of the central Wasatch Mountains, Utah

    Science.gov (United States)

    John, D.A.

    1989-01-01

    Nine mid-Tertiary calc-alkaline stocks, a subvolcanic porphyry system, and coeval volcanic rocks are exposed in a 45-km-long east-trending belt across the central Wasatch Mountains, Utah. The intrusions vary systematically from west to east in texture, style of emplacement, extent of contact metamorphism, hydrothermal alteration, and mineralization. Pressure-depth estimates based on metamorphic mineral assemblages, stratigraphic reconstructions, and fluid inclusion data indicate a regular variation in paleodepths ranging from about 11 km on the west to less than 1 km on the east. These data indicate that the central Wasatch Mountains have been tilted down to the east about 20?? during the late Cenozoic. Fluid inclusion populations in igneous quartz also vary systematically with paleodepth. -from Author

  3. Numerical simulation of the Kuroshio intrusion into the South China Sea by a passive tracer

    Institute of Scientific and Technical Information of China (English)

    LIU Tongya; XU Jiexin; HE Yinghui; L Haibin; YAO Yuan; CAI Shuqun

    2016-01-01

    Owing to lack of observational data and accurate definition, it is difficult to distinguish the Kuroshio intrusion water from the Pacific Ocean into the South China Sea (SCS). By using a passive tracer to identify the Kuroshio water based on an observation-validated three-dimensional numerical model MITgcm, the spatio-temporal variation of the Kuroshio intrusion water into the SCS has been investigated. Our result shows the Kuroshio intrusion is of distinct seasonal variation in both horizontal and vertical directions. In winter, the intruding Kuroshio water reaches the farthest, almost occupying the area from 18°N to 23°N and 114°E to 121°E, with a small branch flowing towards the Taiwan Strait. The intrusion region of the Kuroshio water decreases with depth gradually. However, in summer, the Kuroshio water is confined to the east of 118°E without any branch reaching the Taiwan Strait; meanwhile the intrusion region of the Kuroshio water increases from the surface to the depth about 205 m, then it decreases with depth. The estimated annual mean of Kuroshio Intrusion Transport (KIT) via the Luzon Strait is westward to the SCS in an amount of –3.86×106 m3/s, which is larger than the annual mean of Luzon Strait Transport (LST) of –3.15×106 m3/s. The KIT above 250 m accounts for 60%–80% of the LST throughout the entire water column. By analyzing interannual variation of the Kuroshio intrusion from the year 2003 to 2012, we find that the Kuroshio branch flowing into the Taiwan Strait is the weaker in winter of La Niña years than those in El Niño and normal years, which may be attributed to the wind stress curl off the southeast China then. Furthermore, the KIT correlates the Niño 3.4 index from 2003 to 2012 with a correlation coefficient of 0.41, which is lower than that of the LST with the Niño 3.4 index, i.e., 0.78.

  4. Uncertainty of GIA models across the Greenland

    Science.gov (United States)

    Ruggieri, Gabriella

    2013-04-01

    In the last years various remote sensing techniques have been employed to estimate the current mass balance of the Greenland ice sheet (GIS). In this regards GRACE, laser and radar altimetry observations, employed to constrain the mass balance, consider the glacial isostatic adjustment (GIA) a source of noise. Several GIA models have been elaborated for the Greenland but they differ from each other for mantle viscosity profile and for time history of ice melting. In this work we use the well know ICE-5G (VM2) ice model by Peltier (2004) and two others alternative scenarios of ice melting, ANU05 by Lambeck et al. (1998) and the new regional ice model HUY2 by Simpson et al. (2009) in order to asses the amplitude of the uncertainty related to the GIA predictions. In particular we focus on rates of vertical displacement field, sea surface variations and sea-level change at regional scale. The GIA predictions are estimated using an improved version of SELEN code that solve the sea-level equation for a spherical self-gravitating, incompressible and viscoelastic Earth structure. GIA uncertainty shows a highly variable geographic distribution across the Greenland. Considering the spatial pattern of the GIA predictions related to the three ice models, the western sector of the Greenland Ice Sheets (GrIS) between Thule and Upernavik and around the area of Paamiut, show good agreement while the northeast portion of the Greenland is characterized by a large discrepancy of the GIA predictions inferred by the ice models tested in this work. These differences are ultimately the consequence of the different sets of global relative sea level data and modern geodetic observations used by the authors to constrain the model parameters. Finally GPS Network project (GNET), recently installed around the periphery of the GrIS, are used as a tool to discuss the discrepancies among the GIA models. Comparing the geodetic analysis recently available, appears that among the GPS sites the

  5. The state of the art in intrusion prevention and detection

    CERN Document Server

    Pathan, Al-Sakib Khan

    2013-01-01

    The State of the Art in Intrusion Prevention and Detection analyzes the latest trends and issues surrounding intrusion detection systems in computer networks, especially in communications networks. Its broad scope of coverage includes wired, wireless, and mobile networks; next-generation converged networks; and intrusion in social networks.Presenting cutting-edge research, the book presents novel schemes for intrusion detection and prevention. It discusses tracing back mobile attackers, secure routing with intrusion prevention, anomaly detection, and AI-based techniques. It also includes infor

  6. Research on IPv6 intrusion detection system Snort-based

    Science.gov (United States)

    Shen, Zihao; Wang, Hui

    2010-07-01

    This paper introduces the common intrusion detection technologies, discusses the work flow of Snort intrusion detection system, and analyzes IPv6 data packet encapsulation and protocol decoding technology. We propose the expanding Snort architecture to support IPv6 intrusion detection in accordance with CIDF standard combined with protocol analysis technology and pattern matching technology, and present its composition. The research indicates that the expanding Snort system can effectively detect various intrusion attacks; it is high in detection efficiency and detection accuracy and reduces false alarm and omission report, which effectively solves the problem of IPv6 intrusion detection.

  7. GREENLAND ICE SHEET CHANGES FROM SPACE USING LASER, RADAR AND

    DEFF Research Database (Denmark)

    Sørensen, Louise Sandberg; Stenseng, Lars; Simonsen, Sebastian Bjerregaard

    2010-01-01

    The Greenland cryosphere is undergoing rapid changes, and these are documented by remote sensing from space. In this paper, an inversion scheme is used to derive mass changes from gravity changes observed by GRACE, and to derive the mean annual mass loss for the Greenland Ice Sheet, which is esti...

  8. Holocene insect remains from south-western Greenland

    DEFF Research Database (Denmark)

    Bøcher, Jens Jensenius; Bennike, Ole; Wagner, Bernd

    2012-01-01

    Remains of plants and invertebrates from Holocene deposits in south-western Greenland include a number of insect fragments from Heteroptera and Coleoptera. Some of the finds extend the known temporal range of the species considerably back in time, and one of the taxa has not previously been found...... of terrestrial insects complement the scarce fossil Greenland record of the species concerned....

  9. A checklist of the fish fauna of Greenland waters

    DEFF Research Database (Denmark)

    Møller, Peter R.; Nielsen, Jørgen G.; Knudsen, Steen W.

    2010-01-01

    Although the Greenland fish fauna has been studied for more than 200 years, new species continue to be discovered. We here take the opportunity of the International Polar Year 2007-08 (IPY) to present an updated check-list of the fishes of Greenland and discuss whether the growing diversity can...

  10. Greenland surface albedo changes 1981-2012 from satellite observations

    Science.gov (United States)

    Significant melt over Greenland has been observed during the last several decades associated with extreme warming events over the northern Atlantic Ocean. An analysis of surface albedo change over Greenland is presented, using a 32-year consistent satellite albedo product from the Global Land Surfac...

  11. Greenland island infrastructures – energy challenges to the fishing industry

    DEFF Research Database (Denmark)

    Hendriksen, Kåre

    The most important export industry in Greenland are fisheries - they contribute 90% of the total export value. The local trading and processing is challenged by the fact that Greenland largely depends on island operation, which complicates and limits the infrastructure. For the fishing industry...

  12. Risk factors for Mycobacterium tuberculosis infection among children in Greenland

    DEFF Research Database (Denmark)

    Søborg, Bolette; Andersen, Aase Bengaard; Melbye, Mads

    2011-01-01

    To examine the risk factors for Mycobacterium tuberculosis infection (MTI) among Greenlandic children for the purpose of identifying those at highest risk of infection.......To examine the risk factors for Mycobacterium tuberculosis infection (MTI) among Greenlandic children for the purpose of identifying those at highest risk of infection....

  13. Deglacial History and Paleoceanography of the Umanak System, West Greenland

    DEFF Research Database (Denmark)

    Sheldon, Christina; Jennings, Anne; Andrews, John

    2012-01-01

    A record of Greenland Ice Sheet (GIS) and ice-stream history, ice-sheet ocean interactions and paleoclimate from the Last Glacial Maximum to present is preserved in the sediments of the Umanak fjord, shelf trough and trough mouth fan system of central West Greenland. The objective of this study i...

  14. Eemian interglacial reconstructed from a Greenland folded ice core

    NARCIS (Netherlands)

    Dahl-Jensen, D.; Albert, M.; Roeckmann, T.; Zheng, J.

    2013-01-01

    Efforts to extract a Greenland ice core with a complete record of the Eemian interglacial (130,000 to 115,000 years ago) have until now been unsuccessful. The response of the Greenland ice sheet to the warmer-than-present climate of the Eemian has thus remained unclear. Here we present the new North

  15. Climate Change and Baleen Whale Trophic Cascades in Greenland

    Science.gov (United States)

    2009-09-30

    DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. Climate Change and Baleen Whale Trophic Cascades in Greenland...SUBTITLE Climate Change And Baleen Whale Trophic Cascades In Greenland 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S

  16. The intercultural challenges of engineering education in a Greenlandic context

    DEFF Research Database (Denmark)

    Hendriksen, Kåre; Christensen, Hans Peter

    2014-01-01

    beyond public school. Since 2001 the Technical University of Denmark has offered a study program in Arctic Engineering primarily targeted at Greenlandic youth, but also students from, for example, Denmark, where the first three semesters are finished in Greenland. There are two main objectives...

  17. ISDTM:An Intrusion Signatures Description Temporal Model

    Institute of Scientific and Technical Information of China (English)

    OuYangMing-guang; ZhouYang-bo

    2003-01-01

    ISDTM, based on an augmented Allen's interval temporal logic (ITL) and first-order predicate calculus, is a formal temporal model for representing intrusion signatures.It is augmented with some real time extensions which enhance the expressivity. Intrusion scenarios usually are the set of events and system states, wherethe temporal sequence is their basic relation. Intrusion signatures description, therefore, is to represent such temporal relations in a sense. While representing these signatures, ISDTM decomposes the intrusion process into the sequence of events according to their relevant intervals, and then specifies network states in these Intervals. The uncertain intrusion signatures as well as basic temporal modes of events, which consist of the parallel mode,the sequential mode and the hybrid mode, can be succinctly and naturally represented in ISDTM. Mode chart is the visualization of intrusion signatures in ISDTM, which makes the formulas more readable. The intrusion signatures descriptions in ISDTM have advantages of compact construct, concise syntax, scalability and easy implementation.

  18. A Comprehensive Study in Data Mining Frameworks for Intrusion Detection

    Directory of Open Access Journals (Sweden)

    R.Venkatesan

    2012-12-01

    Full Text Available Intrusions are the activities that violate the security policy of system. Intrusion Detection is the process used to identify intrusions. Network security is to be considered as a major issue in recent years, since the computer network keeps on expanding every day. An Intrusion Detection System (IDS is a system for detecting intrusions and reporting to the authority or to the network administration. Data mining techniques have been successfully applied in many fields like Network Management, Education, Science, Business, Manufacturing, Process control, and Fraud Detection. Data Mining for IDS is the technique which can be used mainly to identify unknown attacks and to raise alarms when security violations are detected. The purpose of this survey paper is to describe the methods/ techniques which are being used for Intrusion Detection based on Data mining concepts and the designed frame works for the same. We are also going to review the related works for intrusion detection.

  19. Using Jquery with Snort to Visualize Intrusion

    Directory of Open Access Journals (Sweden)

    Alaa El - Din Riad

    2012-01-01

    Full Text Available The explosive growth of malicious activities on worldwide communication networks, such as the Internet, has highlighted the need for efficient intrusion detection systems. The efficiency of traditional intrusion detection systems is limited by their inability to effectively relay relevant information due to their lack of interactive / immersive technologies. Visualized information is a technique that can encode large amounts of complex interrelated data, being at the same time easily quantified, manipulated, and processed by a human user. Authors have found that the representations can be quite effective at conveying the needed information and resolving the relationships extremely rapidly. To facilitate the creation of novel visualizations this paper presents a new framework that is designed with using data visualization technique by using Jquery Php for analysis and visualizes snort result data for user.

  20. Iron isotope systematics of the Skaergaard intrusion

    DEFF Research Database (Denmark)

    Lesher, Charles; Lundstrom, C.C.; Barfod, Gry

    report the results of a broad study of the iron isotope compositions of gabbros within the layered and upper border series of the Skaergaard intrusion, pegmatite and granophyre associated with these gabbroic rocks, and the sandwich horizon thought to represent the product of extreme differentiation and/or...... crystallization on non-traditional stable isotope systems, particularly iron. FeTi oxide minerals (titanomagnetite and ilmenite) appear after ~60% of the magma had solidified. This was a significant event affecting the liquid line of descent and potentially accompanied by iron isotope fractionation. Here we...... liquid immiscibility. Forty-eight whole rock samples from well-constrained stratigraphic levels in the intrusion were crushed, powdered and dissolved, followed by iron separation by ion chromatography. Purified solutions were analyzed by MC- ICPMS in high-resolution mode using the sample-std bracket...